This topic describes how to list all objects, a specific number of objects, and objects whose names contain a specific prefix in a bucket.
Usage notes
In this topic, the public endpoint of the China (Hangzhou) region is used. If you want to access OSS by using other Alibaba Cloud services in the same region as OSS, use an internal endpoint. For more information about the regions and endpoints supported by OSS, see Regions and endpoints.
In this topic, access credentials are obtained from environment variables. For more information about how to configure access credentials, see Configure access credentials.
In this topic, an OSSClient instance is created by using an OSS endpoint. If you want to create an OSSClient instance by using custom domain names or Security Token Service (STS), see Create an OSSClient instance.
To list objects, you must have the
oss:ListObjectspermission. For more information, see Common examples of RAM policies.
Background information
You can call the GetBucket (ListObjects) or GetBucketV2 (ListObjectsV2) operation to list up to 1,000 objects in a bucket at a time. You can configure parameters to list objects in different ways. For example, you can configure parameters to list objects from a specific start position, list objects and subdirectories in a specific directory, or list objects by page. The following section describes the differences of the GetBucket (ListObjects) and GetBucketV2 (ListObjectsV2) operations:
When you call the GetBucket (ListObjects) operation to list objects, the object owner information is included in the response.
When you call the GetBucketV2 (ListObjectsV2) operation to list objects, you can configure the fetchOwner parameter to specify whether to include the object owner information in the response.
NoteTo list objects in a versioned bucket, we recommend that you call the GetBucketV2 (ListObjectsV2) operation.
The following tables describe the parameters that you can configure when you call the GetBucket (ListObjects) or GetBucketV2 (ListObjectsV2) operation to list objects.
GetBucket (ListObjects)
You can call the GetBucket (ListObjects) operation in one of the following formats:
ObjectListing listObjects(String bucketName): lists all objects in a bucket. By default, up to 100 objects can be listed by a single request.
ObjectListing listObjects(String bucketName, String prefix): lists objects whose names contain a specific prefix in a bucket. By default, up to 100 objects can be listed by a single request.
ObjectListing listObjects(ListObjectsRequest listObjectsRequest): lists objects that meet specified conditions. You can use this format to list objects in a flexible manner.
The following table describes the parameters that you can specify when you call the GetBucket (ListObjects) operation.
Parameter
Description
Method
objectSummaries
The metadata of the objects that you want to list.
List<OSSObjectSummary> getObjectSummaries()
prefix
The prefix in the names of the objects that you want to list.
String getPrefix()
delimiter
The character used to group the objects that you want to list by name.
String getDelimiter()
marker
The position from which the list operation starts.
String getMarker()
maxKeys
The maximum number of objects that can be listed at a time.
int getMaxKeys()
nextMarker
The position from which the next list operation starts.
String getNextMarker()
isTruncated
Specifies whether the object listing is truncated. Valid values:
false: All objects are listed without truncation.
true: Only a part of the objects are listed.
boolean isTruncated()
commonPrefixes
A set of substrings of object names. Objects whose names end with the delimiter and contain the same prefix are grouped as a single result element in CommonPrefixes.
List<String> getCommonPrefixes()
encodingType
The encoding type of the object names in the response.
String getEncodingType()
GetBucketV2 (ListObjectsV2)
You can call the GetBucketV2 (ListObjectsV2) operation in one of the following formats:
ListObjectsV2Result listObjectsV2(String bucketName): lists all objects in a bucket. By default, up to 100 objects can be listed by a single request.
ListObjectsV2Result listObjectsV2(String bucketName, String prefix): lists objects whose names contain a specific prefix in a bucket. By default, up to 100 objects can be listed by a single request.
ListObjectsV2Result listObjectsV2(ListObjectsRequest listObjectsRequest): lists objects that meet specified conditions. You can use this format to list objects in a flexible manner.
The following table describes the parameters that you can specify when you call the GetBucketV2 (ListObjectsV2) operation.
Parameter
Description
Method
objectSummaries
The metadata of the objects that you want to list.
List<OSSObjectSummary> getObjectSummaries()
prefix
The prefix in the names of the objects that you want to list.
String getPrefix()
delimiter
The character used to group the objects that you want to list by name.
String getDelimiter()
startAfter
The position from which the list operation starts.
String getStartAfter()
maxKeys
The maximum number of objects that can be listed at a time.
int getMaxKeys()
continuationToken
The continuationToken that is used in the list operation.
String getContinuationToken()
nextContinuationToken
The continuationToken that is used in the next list operation.
String getNextContinuationToken()
isTruncated
Specifies whether the object listing is truncated. Valid values:
false: All objects are listed without truncation.
true: Only a part of the objects are listed.
boolean isTruncated()
commonPrefixes
A set of substrings of object names. Objects whose names end with the delimiter and contain the same prefix are grouped as a single result element in CommonPrefixes.
List<String> getCommonPrefixes()
encodingType
The encoding type of the object names in the response.
String getEncodingType()
fetchOwner
Specifies whether to include the object owner information in the response. Valid values:
true
false
String getFetchOwner()
List objects by using a simple list request
You can call the GetBucket (ListObjects) operation or the GetBucketV2 (ListObjectsV2) operation to list objects in a specific bucket.
Call the GetBucket (ListObjects) operation to list objects
The following sample code provides an example on how to call the GetBucket (ListObjects) operation to list objects in a specific bucket. By default, 100 objects are listed by a request.
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args) throws Exception {
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Specify the prefix in the names of the objects that you want to list. Example: exampledir/object.
String keyPrefix = "exampledir/object";
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
// List objects. If you do not specify keyPrefix, all objects in the bucket are listed. If you specify keyPrefix, the objects whose names contain the specified prefix are listed.
ObjectListing objectListing = ossClient.listObjects(bucketName, keyPrefix);
List<OSSObjectSummary> sums = objectListing.getObjectSummaries();
for (OSSObjectSummary s : sums) {
System.out.println("\t" + s.getKey());
}
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
} Call the GetBucketV2 (ListObjectsV2) operation to list objects
The following sample code provides an example on how to call the GetBucketV2 (ListObjectsV2) operation to list objects in a specific bucket. By default, 100 objects are listed by a request.
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args) throws Exception {
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Specify the prefix in the names of the objects that you want to list. Example: exampledir/object.
String keyPrefix = "exampledir/object";
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
// List objects. If you do not specify keyPrefix, all objects in the bucket are listed. If you specify keyPrefix, the objects whose names contain the specified prefix are listed.
ListObjectsV2Result result = ossClient.listObjectsV2(bucketName, keyPrefix);
List<OSSObjectSummary> ossObjectSummaries = result.getObjectSummaries();
for (OSSObjectSummary s : ossObjectSummaries) {
System.out.println("\t" + s.getKey());
}
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}Call the ListObjectsRequest operation to list objects
You can specify parameters when you call the ListObjectsRequest operation to list objects in a flexible manner. The following table describes the parameters that you can specify when you call the ListObjectsRequest operation.
Parameter | Description | Method |
prefix | The prefix that must be included in the names of objects you want to list. | setPrefix(String prefix) |
delimiter | The character used to group the objects that you want to list by name. Objects whose names contain the same string that stretches from the specified prefix to the first delimiter after the prefix are grouped as a CommonPrefixes element. | setDelimiter(String delimiter) |
marker | The position from which the list operation starts. All objects whose names are alphabetically after the value of marker are listed. | setMarker(String marker) |
maxKeys | The maximum number of objects to return. After you specify this parameter, objects are listed in alphabetical order. Maximum value: 1000. Default value: 100. | setMaxKeys(Integer maxKeys) |
encodingType | The encoding type of the object names in the response. Only URL encoding is supported. | setEncodingType(String encodingType) |
List a specified number of objects in a bucket
The following sample code provides an example on how to list a specified number of objects:
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args){
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
// Specify the maximum number of objects that this operation can list.
final int maxKeys = 200;
// List objects.
ObjectListing objectListing = ossClient.listObjects(new ListObjectsRequest(bucketName).withMaxKeys(maxKeys));
List<OSSObjectSummary> sums = objectListing.getObjectSummaries();
for (OSSObjectSummary s : sums) {
System.out.println("\t" + s.getKey());
}
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
} List objects whose names contain a specified prefix
The following sample code provides an example on how to list objects whose names contain a specified prefix:
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args){
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Specify the prefix in the names of the objects that you want to list. Example: exampledir/object.
String keyPrefix = "exampledir/object";
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
// List objects whose names contain the specified prefix. By default, a maximum of 100 objects are listed.
ObjectListing objectListing = ossClient.listObjects(new ListObjectsRequest(bucketName).withPrefix(keyPrefix));
List<OSSObjectSummary> sums = objectListing.getObjectSummaries();
for (OSSObjectSummary s : sums) {
System.out.println("\t" + s.getKey());
}
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
} List objects whose names are alphabetically after the object specified by Marker
You can configure the marker parameter to specify the name of the object after which the list operation starts. The following sample code provides an example on how to list objects whose names are alphabetically after the value of the marker parameter:
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args){
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Specify the marker parameter. Example: exampleobject.txt.
String marker = "exampleobject.txt";
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
// List objects whose names are alphabetically after the specified marker. By default, a maximum of 100 objects are listed.
ObjectListing objectListing = ossClient.listObjects(new ListObjectsRequest(bucketName).withMarker(marker));
List<OSSObjectSummary> sums = objectListing.getObjectSummaries();
for (OSSObjectSummary s : sums) {
System.out.println("\t" + s.getKey());
}
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}List all objects by page
The following sample code provides an example on how to list all objects in a specified bucket by page. You can use maxKeys to specify the maximum number of objects that can be listed on each page.
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args){
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Set maxKeys to 200.
int maxKeys = 200;
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
String nextMarker = null;
ObjectListing objectListing;
do {
objectListing = ossClient.listObjects(new ListObjectsRequest(bucketName).withMarker(nextMarker).withMaxKeys(maxKeys));
List<OSSObjectSummary> sums = objectListing.getObjectSummaries();
for (OSSObjectSummary s : sums) {
System.out.println("\t" + s.getKey());
}
nextMarker = objectListing.getNextMarker();
} while (objectListing.isTruncated());
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}List objects whose names contain a specified prefix by page
The following sample code provides an example on how to list objects whose names contain a specified prefix by page:
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args){
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Set maxKeys to 200.
int maxKeys = 200;
// Specify the prefix in the names of the objects that you want to list. Example: exampledir/object.
String keyPrefix = "exampledir/object";
// Specify the marker parameter. Example: objecttest.txt.
String nextMarker = "objecttest.txt";
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
ObjectListing objectListing;
do {
objectListing = ossClient.listObjects(new ListObjectsRequest(bucketName).
withPrefix(keyPrefix).withMarker(nextMarker).withMaxKeys(maxKeys));
List<OSSObjectSummary> sums = objectListing.getObjectSummaries();
for (OSSObjectSummary s : sums) {
System.out.println("\t" + s.getKey());
}
nextMarker = objectListing.getNextMarker();
} while (objectListing.isTruncated());
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}List objects whose names are encoded by using a specific encoding type
An object name that contains one of the following special characters must be encoded before the object is transmitted. OSS supports only URL encoding.
Single quotation marks (')
Double quotation marks (")
Ampersands (&)
Angle brackets (<>)
Pause markers (、)
Chinese characters
The following sample code provides an example on how to list objects whose names are encoded by using a specific encoding type:
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.net.URLDecoder;
public class Demo {
public static void main(String[] args) throws Exception {
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Set maxKeys to 200.
int maxKeys = 200;
// Specify the prefix in the names of the objects that you want to list. Example: exampledir/object.
String keyPrefix = "exampledir/object";
// Specify the marker parameter. Example: objecttest.txt.
String nextMarker = "objecttest.txt";
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
ObjectListing objectListing;
do {
ListObjectsRequest listObjectsRequest = new ListObjectsRequest(bucketName);
listObjectsRequest.setPrefix(keyPrefix);
listObjectsRequest.setMaxKeys(maxKeys);
listObjectsRequest.setMarker(nextMarker);
// Specify the encoding type of the object names.
listObjectsRequest.setEncodingType("url");
objectListing = ossClient.listObjects(listObjectsRequest);
// Decode the value of Key in the response.
for (OSSObjectSummary objectSummary: objectListing.getObjectSummaries()) {
System.out.println("Key:" + URLDecoder.decode(objectSummary.getKey(), "UTF-8"));
}
// Decode the value of CommonPrefixes in the response.
for (String commonPrefixes: objectListing.getCommonPrefixes()) {
System.out.println("CommonPrefixes:" + URLDecoder.decode(commonPrefixes, "UTF-8"));
}
// Decode the value of nextMarker in the response.
if (objectListing.getNextMarker() != null) {
nextMarker = URLDecoder.decode(objectListing.getNextMarker(), "UTF-8");
}
} while (objectListing.isTruncated());
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}Call the ListObjectsV2Request operation to list objects
You can specify parameters when you call the ListObjectsV2Request operation to list objects in a flexible manner. For example, you can list a specified number of objects, objects whose names contain a specific prefix, or all objects in a bucket by page.
The following table describes the parameters that you can specify when you call the ListObjectsV2Request operation.
Parameter | Description | Method |
prefix | The prefix that must be included in the names of objects you want to list. | setPrefix(String prefix) |
delimiter | The character used to group the objects that you want to list by name. Objects whose names contain the same string that stretches from the specified prefix to the first delimiter after the prefix are grouped as a CommonPrefixes element. | setDelimiter(String delimiter) |
maxKeys | The maximum number of objects to return. After you specify this parameter, objects are listed in alphabetical order. Maximum value: 1000. Default value: 100. | setMaxKeys(Integer maxKeys) |
startAfter | The position from which the list operation starts. Objects whose names are alphabetically after the value of startAfter are listed. | setStartAfter(String startAfter) |
continuationToken | The continuationToken that is used in this list operation. | setContinuationToken(String continuationToken) |
encodingType | The encoding type of the object names in the response. Only URL encoding is supported. | setEncodingType(String encodingType) |
fetchOwner | Specifies whether to include the owner information in the response. | setFetchOwner(boolean fetchOwner ) |
List a specified number of objects in a bucket
The following sample code provides an example on how to list a specified number of objects:
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args) throws Exception {
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Specify the maximum number of objects that this operation can list.
int maxKeys = 200;
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
// List objects. By default, 100 objects are returned by a single request. In this example, up to 200 objects can be returned at a time.
ListObjectsV2Request listObjectsV2Request = new ListObjectsV2Request(bucketName);
listObjectsV2Request.setMaxKeys(maxKeys);
ListObjectsV2Result result = ossClient.listObjectsV2(listObjectsV2Request);
List<OSSObjectSummary> ossObjectSummaries = result.getObjectSummaries();
for (OSSObjectSummary s : ossObjectSummaries) {
System.out.println("\t" + s.getKey());
}
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}List objects whose names contain a specified prefix
The following sample code provides an example on how to list objects whose names contain a specified prefix:
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args) throws Exception {
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Specify the prefix in the names of the objects that you want to list. Example: exampledir/object.
String prefix = "exampledir/object";
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
// List objects.
ListObjectsV2Request listObjectsV2Request = new ListObjectsV2Request(bucketName);
listObjectsV2Request.setPrefix(prefix);
ListObjectsV2Result result = ossClient.listObjectsV2(listObjectsV2Request);
List<OSSObjectSummary> ossObjectSummaries = result.getObjectSummaries();
for (OSSObjectSummary s : ossObjectSummaries) {
System.out.println("\t" + s.getKey());
}
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}List objects whose names are alphabetically after the object specified by startAfter
The following sample code provides an example on how to list objects whose names are alphabetically after the object specified by startAfter:
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args) throws Exception {
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
// List objects whose names are alphabetically after the object specified by startAfter. The value of startAfter can be the name of an existing object or other strings.
// For example, if you set startAfter to test-obj, objects whose names are alphabetically after the test-obj string are returned. The object named test-obj is not listed even if the object exists in the bucket.
ListObjectsV2Request listObjectsV2Request = new ListObjectsV2Request(bucketName);
listObjectsV2Request.setStartAfter("test-obj");
ListObjectsV2Result result = ossClient.listObjectsV2(listObjectsV2Request);
List<OSSObjectSummary> ossObjectSummaries = result.getObjectSummaries();
for (OSSObjectSummary s : ossObjectSummaries) {
System.out.println("\t" + s.getKey());
}
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}List objects and their owner information
The following sample code provides an example on how to list objects and their owner information:
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args) throws Exception {
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
// By default, the owner information of the objects is not listed. To include the object owner information in the response, set the fetchOwner parameter to true.
ListObjectsV2Request listObjectsV2Request = new ListObjectsV2Request(bucketName);
listObjectsV2Request.setFetchOwner(true);
ListObjectsV2Result result = ossClient.listObjectsV2(listObjectsV2Request);
List<OSSObjectSummary> ossObjectSummaries = result.getObjectSummaries();
for (OSSObjectSummary s : ossObjectSummaries) {
System.out.println("\t" + s.getKey());
if (s.getOwner() != null) {
System.out.println("owner id:" + s.getOwner().getId());
System.out.println("name:" + s.getOwner().getDisplayName());
}
}
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}List all objects by page
The following sample code provides an example on how to list all objects in a specified bucket by page. You can use maxKeys to specify the maximum number of objects that can be listed on each page.
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args) throws Exception {
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Specify the maximum number of objects that this operation can list.
int maxKeys = 200;
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
String nextContinuationToken = null;
ListObjectsV2Result result = null;
// List objects by page by using the nextContinuationToken parameter included in the response of the previous list operation.
do {
ListObjectsV2Request listObjectsV2Request = new ListObjectsV2Request(bucketName).withMaxKeys(maxKeys);
listObjectsV2Request.setContinuationToken(nextContinuationToken);
result = ossClient.listObjectsV2(listObjectsV2Request);
List<OSSObjectSummary> sums = result.getObjectSummaries();
for (OSSObjectSummary s : sums) {
System.out.println("\t" + s.getKey());
}
nextContinuationToken = result.getNextContinuationToken();
} while (result.isTruncated());
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}List objects whose names contain a specified prefix by page
The following sample code provides an example on how to list objects whose names contain a specified prefix by page:
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.List;
public class Demo {
public static void main(String[] args) throws Exception {
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Specify the prefix in the names of the objects that you want to list. Example: exampledir/object.
String keyPrefix = "exampledir/object";
// Specify the maximum number of objects that this operation can list.
int maxKeys = 200;
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
String nextContinuationToken = null;
ListObjectsV2Result result = null;
// List the objects whose names contain the specified prefix by page.
do {
ListObjectsV2Request listObjectsV2Request = new ListObjectsV2Request(bucketName).withMaxKeys(maxKeys);
listObjectsV2Request.setPrefix(keyPrefix);
listObjectsV2Request.setContinuationToken(nextContinuationToken);
result = ossClient.listObjectsV2(listObjectsV2Request);
List<OSSObjectSummary> sums = result.getObjectSummaries();
for (OSSObjectSummary s : sums) {
System.out.println("\t" + s.getKey());
}
nextContinuationToken = result.getNextContinuationToken();
} while (result.isTruncated());
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}List objects whose names are encoded by using a specific encoding type
The following sample code provides an example on how to list objects whose names are encoded by using a specific encoding type:
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.net.URLDecoder;
public class Demo {
public static void main(String[] args) throws Exception {
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint.
String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
// Specify the name of the bucket. Example: examplebucket.
String bucketName = "examplebucket";
// Specify the prefix in the names of the objects that you want to list. Example: exampledir/object.
String keyPrefix = "exampledir/object";
// Specify the maximum number of objects that this operation can list.
int maxKeys = 200;
// Create an OSSClient instance.
OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
try {
String nextContinuationToken = null;
ListObjectsV2Result result = null;
// Specify that the returned results are URL-encoded. In this case, you must decode the values of the prefix, delimiter, startAfter, key, and commonPrefix parameters in the response.
do {
ListObjectsV2Request listObjectsV2Request = new ListObjectsV2Request(bucketName).withMaxKeys(maxKeys);
listObjectsV2Request.setPrefix(keyPrefix);
listObjectsV2Request.setEncodingType("url");
listObjectsV2Request.setContinuationToken(nextContinuationToken);
result = ossClient.listObjectsV2(listObjectsV2Request);
// Decode the value of prefix in the response.
if (result.getPrefix() != null) {
String prefix = URLDecoder.decode(result.getPrefix(), "UTF-8");
System.out.println("prefix: " + prefix);
}
// Decode the value of delimiter in the response.
if (result.getDelimiter() != null) {
String delimiter = URLDecoder.decode(result.getDelimiter(), "UTF-8");
System.out.println("delimiter: " + delimiter);
}
// Decode the value of startAfter in the response.
if (result.getStartAfter() != null) {
String startAfter = URLDecoder.decode(result.getStartAfter(), "UTF-8");
System.out.println("startAfter: " + startAfter);
}
// Decode the value of key in the response.
for (OSSObjectSummary s : result.getObjectSummaries()) {
String decodedKey = URLDecoder.decode(s.getKey(), "UTF-8");
System.out.println("key: " + decodedKey);
}
// Decode the value of CommonPrefixes in the response.
for (String commonPrefix: result.getCommonPrefixes()) {
String decodeCommonPrefix = URLDecoder.decode(commonPrefix, "UTF-8");
System.out.println("CommonPrefix:" + decodeCommonPrefix);
}
nextContinuationToken = result.getNextContinuationToken();
} while (result.isTruncated());
} catch (OSSException oe) {
System.out.println("Caught an OSSException, which means your request made it to OSS, "
+ "but was rejected with an error response for some reason.");
System.out.println("Error Message:" + oe.getErrorMessage());
System.out.println("Error Code:" + oe.getErrorCode());
System.out.println("Request ID:" + oe.getRequestId());
System.out.println("Host ID:" + oe.getHostId());
} catch (ClientException ce) {
System.out.println("Caught an ClientException, which means the client encountered "
+ "a serious internal problem while trying to communicate with OSS, "
+ "such as not being able to access the network.");
System.out.println("Error Message:" + ce.getMessage());
} finally {
if (ossClient != null) {
ossClient.shutdown();
}
}
}
}List objects by directory
OSS uses a flat structure to store objects. A directory is a zero-byte object whose name ends with a forward slash (/). You can upload and download a directory. By default, an object whose name ends with a forward slash (/) is displayed as a directory in the OSS console. For the complete sample code for creating directories, visit GitHub.
You can specify the delimiter and prefix parameters to list objects by directory.
If you set prefix to a directory name in the request, the objects and subdirectories whose names contain the prefix are listed.
If you specify a prefix and set delimiter to a forward slash (/) in the request, the objects and subdirectories whose names start with the specified prefix in the directory are listed. Each subdirectory is listed as a single result element in CommonPrefixes. The objects and directories in these subdirectories are not listed.
Assume that a bucket contains the following objects: oss.jpg, fun/test.jpg, fun/movie/001.avi, and fun/movie/007.avi. The forward slash (/) is specified as the directory delimiter. The following examples describe how to list objects in simulated directories.
List all objects in the bucket
The following sample code provides an example on how to call the GetBucket (ListObjects) operation to list all objects in the bucket:
import com.aliyun.oss.ClientException; import com.aliyun.oss.OSS; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.OSSClientBuilder; import com.aliyun.oss.OSSException; import com.aliyun.oss.model.*; public class Demo { public static void main(String[] args) throws Exception { // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. String endpoint = "https://oss-cn-hangzhou.aliyuncs.com"; // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider(); // Specify the name of the bucket. Example: examplebucket. String bucketName = "examplebucket"; // Create an OSSClient instance. OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider); try { // Create a request to list objects. ListObjectsRequest listObjectsRequest = new ListObjectsRequest(bucketName); // List objects. ObjectListing listing = ossClient.listObjects(listObjectsRequest); // Traverse all objects. System.out.println("Objects:"); for (OSSObjectSummary objectSummary : listing.getObjectSummaries()) { System.out.println(objectSummary.getKey()); } // Traverse all CommonPrefix elements. System.out.println("CommonPrefixes:"); for (String commonPrefix : listing.getCommonPrefixes()) { System.out.println(commonPrefix); } } catch (OSSException oe) { System.out.println("Caught an OSSException, which means your request made it to OSS, " + "but was rejected with an error response for some reason."); System.out.println("Error Message:" + oe.getErrorMessage()); System.out.println("Error Code:" + oe.getErrorCode()); System.out.println("Request ID:" + oe.getRequestId()); System.out.println("Host ID:" + oe.getHostId()); } catch (ClientException ce) { System.out.println("Caught an ClientException, which means the client encountered " + "a serious internal problem while trying to communicate with OSS, " + "such as not being able to access the network."); System.out.println("Error Message:" + ce.getMessage()); } finally { if (ossClient != null) { ossClient.shutdown(); } } } }The following sample code provides an example on how to call the GetBucketV2 (ListObjectsV2) operation to list all objects in the bucket:
import com.aliyun.oss.ClientException; import com.aliyun.oss.OSS; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.OSSClientBuilder; import com.aliyun.oss.OSSException; import com.aliyun.oss.model.*; public class Demo { public static void main(String[] args) throws Exception { // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. String endpoint = "https://oss-cn-hangzhou.aliyuncs.com"; // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider(); // Specify the name of the bucket. Example: examplebucket. String bucketName = "examplebucket"; // Create an OSSClient instance. OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider); try { // List objects. ListObjectsV2Request listObjectsV2Request = new ListObjectsV2Request(bucketName); ListObjectsV2Result result = ossClient.listObjectsV2(listObjectsV2Request); // Traverse all objects. System.out.println("Objects:"); for (OSSObjectSummary objectSummary : result.getObjectSummaries()) { System.out.println(objectSummary.getKey()); } // Traverse all CommonPrefix elements. System.out.println("CommonPrefixes:"); for (String commonPrefix : result.getCommonPrefixes()) { System.out.println(commonPrefix); } } catch (OSSException oe) { System.out.println("Caught an OSSException, which means your request made it to OSS, " + "but was rejected with an error response for some reason."); System.out.println("Error Message:" + oe.getErrorMessage()); System.out.println("Error Code:" + oe.getErrorCode()); System.out.println("Request ID:" + oe.getRequestId()); System.out.println("Host ID:" + oe.getHostId()); } catch (ClientException ce) { System.out.println("Caught an ClientException, which means the client encountered " + "a serious internal problem while trying to communicate with OSS, " + "such as not being able to access the network."); System.out.println("Error Message:" + ce.getMessage()); } finally { if (ossClient != null) { ossClient.shutdown(); } } } }Sample response
The following response is returned for the preceding two methods that list all objects in the bucket:
Objects: fun/movie/001.avi fun/movie/007.avi fun/test.jpg oss.jpg CommonPrefixes:
List all objects in a directory
The following sample code provides an example on how to call the GetBucket (ListObjects) operation to list all objects in a directory:
import com.aliyun.oss.ClientException; import com.aliyun.oss.OSS; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.OSSClientBuilder; import com.aliyun.oss.OSSException; import com.aliyun.oss.model.*; public class Demo { public static void main(String[] args) throws Exception { // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. String endpoint = "https://oss-cn-hangzhou.aliyuncs.com"; // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider(); // Specify the name of the bucket. Example: examplebucket. String bucketName = "examplebucket"; // Create an OSSClient instance. OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider); try { // Create a request to list objects. ListObjectsRequest listObjectsRequest = new ListObjectsRequest(bucketName); // Set prefix to fun/ to list all objects in the fun/ directory. listObjectsRequest.setPrefix("fun/"); // Lists all objects in the fun/ directory. ObjectListing listing = ossClient.listObjects(listObjectsRequest); // Traverse all objects. System.out.println("Objects:"); for (OSSObjectSummary objectSummary : listing.getObjectSummaries()) { System.out.println(objectSummary.getKey()); } // Traverse all CommonPrefix elements. System.out.println("\nCommonPrefixes:"); for (String commonPrefix : listing.getCommonPrefixes()) { System.out.println(commonPrefix); } } catch (OSSException oe) { System.out.println("Caught an OSSException, which means your request made it to OSS, " + "but was rejected with an error response for some reason."); System.out.println("Error Message:" + oe.getErrorMessage()); System.out.println("Error Code:" + oe.getErrorCode()); System.out.println("Request ID:" + oe.getRequestId()); System.out.println("Host ID:" + oe.getHostId()); } catch (ClientException ce) { System.out.println("Caught an ClientException, which means the client encountered " + "a serious internal problem while trying to communicate with OSS, " + "such as not being able to access the network."); System.out.println("Error Message:" + ce.getMessage()); } finally { if (ossClient != null) { ossClient.shutdown(); } } } }The following sample code provides an example on how to call the GetBucketV2 (ListObjectsV2) operation to list all objects in a directory:
import com.aliyun.oss.ClientException; import com.aliyun.oss.OSS; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.OSSClientBuilder; import com.aliyun.oss.OSSException; import com.aliyun.oss.model.*; public class Demo { public static void main(String[] args) throws Exception { // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. String endpoint = "https://oss-cn-hangzhou.aliyuncs.com"; // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider(); // Specify the name of the bucket. Example: examplebucket. String bucketName = "examplebucket"; // Create an OSSClient instance. OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider); try { // Create a ListObjectsV2Request request to list objects. ListObjectsV2Request listObjectsV2Request = new ListObjectsV2Request(bucketName); // Set prefix to fun/ to list all objects in the fun/ directory. listObjectsV2Request.setPrefix("fun/"); // Initiate the request. ListObjectsV2Result result = ossClient.listObjectsV2(listObjectsV2Request); // Traverse all objects. System.out.println("Objects:"); for (OSSObjectSummary objectSummary : result.getObjectSummaries()) { System.out.println(objectSummary.getKey()); } // Traverse all CommonPrefix elements. System.out.println("\nCommonPrefixes:"); for (String commonPrefix : result.getCommonPrefixes()) { System.out.println(commonPrefix); } } catch (OSSException oe) { System.out.println("Caught an OSSException, which means your request made it to OSS, " + "but was rejected with an error response for some reason."); System.out.println("Error Message:" + oe.getErrorMessage()); System.out.println("Error Code:" + oe.getErrorCode()); System.out.println("Request ID:" + oe.getRequestId()); System.out.println("Host ID:" + oe.getHostId()); } catch (ClientException ce) { System.out.println("Caught an ClientException, which means the client encountered " + "a serious internal problem while trying to communicate with OSS, " + "such as not being able to access the network."); System.out.println("Error Message:" + ce.getMessage()); } finally { if (ossClient != null) { ossClient.shutdown(); } } } }The following response is returned for the preceding two operations that list all objects in the specified directory:
Objects: fun/movie/001.avi fun/movie/007.avi fun/test.jpg CommonPrefixes:
List objects and subdirectories in a directory
The following sample code provides an example on how to call the GetBucket (ListObjects) operation to list objects and subdirectories in a directory:
import com.aliyun.oss.ClientException; import com.aliyun.oss.OSS; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.OSSClientBuilder; import com.aliyun.oss.OSSException; import com.aliyun.oss.model.*; public class Demo { public static void main(String[] args) throws Exception { // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. String endpoint = "https://oss-cn-hangzhou.aliyuncs.com"; // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider(); // Specify the name of the bucket. Example: examplebucket. String bucketName = "examplebucket"; // Create an OSSClient instance. OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider); try { // Create a request to list objects. ListObjectsRequest listObjectsRequest = new ListObjectsRequest(bucketName); // Specify the forward slash (/) as the delimiter. listObjectsRequest.setDelimiter("/"); // List all objects and subdirectories in the fun/ directory. listObjectsRequest.setPrefix("fun/"); ObjectListing listing = ossClient.listObjects(listObjectsRequest); // Traverse all objects. System.out.println("Objects:"); // In the response, objectSummaries lists the objects in the fun/ directory. for (OSSObjectSummary objectSummary : listing.getObjectSummaries()) { System.out.println(objectSummary.getKey()); } // Traverse all CommonPrefix elements. System.out.println("\nCommonPrefixes:"); // CommonPrefixs lists all subdirectories in the fun/ directory. The fun/movie/001.avi and fun/movie/007.avi objects are not listed because they are in the movie subdirectory of the fun/ directory. for (String commonPrefix : listing.getCommonPrefixes()) { System.out.println(commonPrefix); } } catch (OSSException oe) { System.out.println("Caught an OSSException, which means your request made it to OSS, " + "but was rejected with an error response for some reason."); System.out.println("Error Message:" + oe.getErrorMessage()); System.out.println("Error Code:" + oe.getErrorCode()); System.out.println("Request ID:" + oe.getRequestId()); System.out.println("Host ID:" + oe.getHostId()); } catch (ClientException ce) { System.out.println("Caught an ClientException, which means the client encountered " + "a serious internal problem while trying to communicate with OSS, " + "such as not being able to access the network."); System.out.println("Error Message:" + ce.getMessage()); } finally { if (ossClient != null) { ossClient.shutdown(); } } } }The following sample code provides an example on how to call the GetBucketV2 (ListObjectsV2) operation to list objects and subdirectories in a directory:
import com.aliyun.oss.ClientException; import com.aliyun.oss.OSS; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.OSSClientBuilder; import com.aliyun.oss.OSSException; import com.aliyun.oss.model.*; public class Demo { public static void main(String[] args) throws Exception { // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. String endpoint = "https://oss-cn-hangzhou.aliyuncs.com"; // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider(); // Specify the name of the bucket. Example: examplebucket. String bucketName = "examplebucket"; // Create an OSSClient instance. OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider); try { // Create a ListObjectsV2Request request to list objects. ListObjectsV2Request listObjectsV2Request = new ListObjectsV2Request(bucketName); // Set Prefix to fun/ to list all objects and subdirectories in the fun/ directory. listObjectsV2Request.setPrefix("fun/"); // Specify the forward slash (/) as the delimiter. listObjectsV2Request.setDelimiter("/"); // Initiate the request. ListObjectsV2Result result = ossClient.listObjectsV2(listObjectsV2Request); // Traverse all objects. System.out.println("Objects:"); // In the response, objectSummaries lists the objects in the fun/ directory. for (OSSObjectSummary objectSummary : result.getObjectSummaries()) { System.out.println(objectSummary.getKey()); } // Traverse all CommonPrefix elements. System.out.println("\nCommonPrefixes:"); // CommonPrefixs lists all subdirectories in the fun/ directory. The fun/movie/001.avi and fun/movie/007.avi objects are not listed because they are in the movie subdirectory of the fun/ directory. for (String commonPrefix : result.getCommonPrefixes()) { System.out.println(commonPrefix); } } catch (OSSException oe) { System.out.println("Caught an OSSException, which means your request made it to OSS, " + "but was rejected with an error response for some reason."); System.out.println("Error Message:" + oe.getErrorMessage()); System.out.println("Error Code:" + oe.getErrorCode()); System.out.println("Request ID:" + oe.getRequestId()); System.out.println("Host ID:" + oe.getHostId()); } catch (ClientException ce) { System.out.println("Caught an ClientException, which means the client encountered " + "a serious internal problem while trying to communicate with OSS, " + "such as not being able to access the network."); System.out.println("Error Message:" + ce.getMessage()); } finally { if (ossClient != null) { ossClient.shutdown(); } } } }The following response is returned when you call the preceding two operations to list objects and subdirectories in the specified directory:
Objects: fun/test.jpg CommonPrefixes: fun/movie/
List the sizes of objects in a directory
The following sample code provides an example on how to call the GetBucket (ListObjects) operation to list the sizes of objects in a directory:
import com.aliyun.oss.ClientException; import com.aliyun.oss.OSS; import com.aliyun.oss.common.auth.*;import com.aliyun.oss.OSS; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.OSSClientBuilder; import com.aliyun.oss.OSSException; import com.aliyun.oss.model.*; import java.util.List; public class Demo { public static void main(String[] args) throws Exception { // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. String endpoint = "https://oss-cn-hangzhou.aliyuncs.com"; // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider(); // Specify the name of the bucket. Example: examplebucket. String bucketName = "examplebucket"; // Specify the prefix in the names of the objects that you want to list. Example: exampledir/object. If you want to traverse the sizes of objects and directories in the root directory, leave this parameter empty. String keyPrefix = "exampledir/object"; // Create an OSSClient instance. OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider); try { ObjectListing objectListing = null; do { // By default, 100 objects or directories are listed at a time. ListObjectsRequest request = new ListObjectsRequest(bucketName).withDelimiter("/").withPrefix(keyPrefix); if (objectListing != null) { request.setMarker(objectListing.getNextMarker()); } objectListing = ossClient.listObjects(request); List<String> folders = objectListing.getCommonPrefixes(); for (String folder : folders) { System.out.println(folder + " : " + (calculateFolderLength(ossClient, bucketName, folder) / 1024) + "KB"); } List<OSSObjectSummary> sums = objectListing.getObjectSummaries(); for (OSSObjectSummary s : sums) { System.out.println(s.getKey() + " : " + (s.getSize() / 1024) + "KB"); } } while (objectListing.isTruncated()); } catch (OSSException oe) { System.out.println("Caught an OSSException, which means your request made it to OSS, " + "but was rejected with an error response for some reason."); System.out.println("Error Message:" + oe.getErrorMessage()); System.out.println("Error Code:" + oe.getErrorCode()); System.out.println("Request ID:" + oe.getRequestId()); System.out.println("Host ID:" + oe.getHostId()); } catch (ClientException ce) { System.out.println("Caught an ClientException, which means the client encountered " + "a serious internal problem while trying to communicate with OSS, " + "such as not being able to access the network."); System.out.println("Error Message:" + ce.getMessage()); } finally { if (ossClient != null) { ossClient.shutdown(); } } } // List the sizes of objects in a specific directory in a bucket. private static long calculateFolderLength(OSS ossClient, String bucketName, String folder) { long size = 0L; ObjectListing objectListing = null; do { // The default value of MaxKeys is 100. The maximum value of MaxKeys is 1000. ListObjectsRequest request = new ListObjectsRequest(bucketName).withPrefix(folder).withMaxKeys(1000); if (objectListing != null) { request.setMarker(objectListing.getNextMarker()); } objectListing = ossClient.listObjects(request); List<OSSObjectSummary> sums = objectListing.getObjectSummaries(); for (OSSObjectSummary s : sums) { size += s.getSize(); } } while (objectListing.isTruncated()); return size; } }The following sample code provides an example on how to call the GetBucketV2 (ListObjectsV2) operation to list the sizes of objects in a directory:
import com.aliyun.oss.ClientException; import com.aliyun.oss.OSS; import com.aliyun.oss.common.auth.*;import com.aliyun.oss.OSS; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.common.auth.*; import com.aliyun.oss.OSSClientBuilder; import com.aliyun.oss.OSSException; import com.aliyun.oss.model.*; import java.util.List; public class Demo { public static void main(String[] args) throws Exception { // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. String endpoint = "https://oss-cn-hangzhou.aliyuncs.com"; // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider(); // Specify the name of the bucket. Example: examplebucket. String bucketName = "examplebucket"; // Specify the prefix in the names of the objects that you want to list. Example: exampledir/object. If you want to traverse the sizes of objects and directories in the root directory, leave this parameter empty. String keyPrefix = "exampledir/object"; // Create an OSSClient instance. OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider); try { ListObjectsV2Result result = null; do { // By default, 100 objects or directories are listed at a time. ListObjectsV2Request request = new ListObjectsV2Request(bucketName).withDelimiter("/").withPrefix(keyPrefix); if (result != null) { request.setContinuationToken(result.getNextContinuationToken()); } result = ossClient.listObjectsV2(request); List<String> folders = result.getCommonPrefixes(); for (String folder : folders) { System.out.println(folder + " : " + (calculateFolderLength(ossClient, bucketName, folder) / 1024) + "KB"); } List<OSSObjectSummary> sums = result.getObjectSummaries(); for (OSSObjectSummary s : sums) { System.out.println(s.getKey() + " : " + (s.getSize() / 1024) + "KB"); } } while (result.isTruncated()); } catch (OSSException oe) { System.out.println("Caught an OSSException, which means your request made it to OSS, " + "but was rejected with an error response for some reason."); System.out.println("Error Message:" + oe.getErrorMessage()); System.out.println("Error Code:" + oe.getErrorCode()); System.out.println("Request ID:" + oe.getRequestId()); System.out.println("Host ID:" + oe.getHostId()); } catch (ClientException ce) { System.out.println("Caught an ClientException, which means the client encountered " + "a serious internal problem while trying to communicate with OSS, " + "such as not being able to access the network."); System.out.println("Error Message:" + ce.getMessage()); } finally { if (ossClient != null) { ossClient.shutdown(); } } } // List the sizes of objects in a specific directory in a bucket. private static long calculateFolderLength(OSS ossClient, String bucketName, String folder) { long size = 0L; ListObjectsV2Result result = null; do { // The default value of MaxKeys is 100. The maximum value of MaxKeys is 1000. ListObjectsV2Request request = new ListObjectsV2Request(bucketName).withPrefix(folder).withMaxKeys(1000); if (result != null) { request.setContinuationToken(result.getNextContinuationToken()); } result = ossClient.listObjectsV2(request); List<OSSObjectSummary> sums = result.getObjectSummaries(); for (OSSObjectSummary s : sums) { size += s.getSize(); } } while (result.isTruncated()); return size; } }
References
For the complete sample code for listing objects, visit GitHub.
For more information about the API operations that you can call to list objects, see GetBucket (ListObjects) and ListObjectsV2(GetBucketV2).