Object Storage Service:Copying a file (Java SDK V1)

Notes

• In this topic, the public endpoint of the China (Hangzhou) region is used. To access OSS from other Alibaba Cloud services in the same region, use an internal endpoint. For details about supported regions and endpoints, 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 Configuration examples for common scenarios.

• You must have read permissions on the source object and read and write permissions on the destination bucket.

• Ensure that the source and destination buckets do not have a retention policy configured. Otherwise, the copy operation fails and an error is reported: The object you specified is immutable..

• Cross-region copy is not supported. For example, you cannot copy an object from a bucket in the China (Hangzhou) region to a bucket in the China (Qingdao) region.

Copy a small object

You can use the ossClient.copyObject method to copy an object that is smaller than 1 GB. This method supports two ways of specifying parameters:

The following table describes the parameters that you can configure for CopyObjectRequest.

The following table describes the parameters that you can configure for CopyObjectResult.

You can use one of the following methods to copy small objects:

• Simple copy

  The following code provides an example of how to perform a simple copy operation. In this example, the srcexampleobject.txt object is copied from the srcexamplebucket bucket to the desexampleobject.txt object in the desexamplebucket bucket.

  import com.aliyun.oss.*;
  import com.aliyun.oss.common.auth.*;
  import com.aliyun.oss.common.comm.SignVersion;
  import com.aliyun.oss.model.*;
  
  public class Demo {
      public static void main(String[] args) throws Exception {
          // The China (Hangzhou) region is used as an example. Specify the 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 source bucket.
          String sourceBucketName = "srcexamplebucket";
          // Specify the full path of the source object. The full path cannot contain the bucket name.
          String sourceKey = "srcexampleobject.txt";
          // Specify the name of the destination bucket. The destination bucket must be in the same region as the source bucket.
          String destinationBucketName = "desexamplebucket";
          // Specify the full path of the destination object. The full path cannot contain the bucket name.
          String destinationKey = "desexampleobject.txt";
          // Specify the region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set the region to cn-hangzhou.
          String region = "cn-hangzhou";
  
          // Create an OSSClient instance.
          // When the OSSClient instance is no longer used, call the shutdown method to release resources.
          ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
          clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);        
          OSS ossClient = OSSClientBuilder.create()
          .endpoint(endpoint)
          .credentialsProvider(credentialsProvider)
          .clientConfiguration(clientBuilderConfiguration)
          .region(region)               
          .build();
  
          try {
              // Copy the file.
              CopyObjectResult result = ossClient.copyObject(sourceBucketName, sourceKey, destinationBucketName, destinationKey);
              System.out.println("ETag: " + result.getETag() + " LastModified: " + result.getLastModified());
          } 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();
              }
          }
      }
  }                   

• Copy using CopyObjectRequest

  The following code provides an example of how to use CopyObjectRequest to copy the srcexampleobject.txt object from the srcexamplebucket bucket to the desexampleobject.txt object in the desexamplebucket bucket.

  import com.aliyun.oss.*;
  import com.aliyun.oss.common.auth.*;
  import com.aliyun.oss.common.comm.SignVersion;
  import com.aliyun.oss.model.*;
  
  public class Demo {
      public static void main(String[] args) throws Exception {
          // The China (Hangzhou) region is used as an example. Specify the 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 source bucket.
          String sourceBucketName = "srcexamplebucket";
          // Specify the full path of the source object. The full path cannot contain the bucket name.
          String sourceKey = "srcexampleobject.txt";
          // Specify the name of the destination bucket. The destination bucket must be in the same region as the source bucket.
          String destinationBucketName = "desexamplebucket";
          // Specify the full path of the destination object. The full path cannot contain the bucket name.
          String destinationKey = "desexampleobject.txt";
          // Specify the region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set the region to cn-hangzhou.
          String region = "cn-hangzhou";
  
          // Create an OSSClient instance.
          // When the OSSClient instance is no longer used, call the shutdown method to release resources.
          ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
          clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);        
          OSS ossClient = OSSClientBuilder.create()
          .endpoint(endpoint)
          .credentialsProvider(credentialsProvider)
          .clientConfiguration(clientBuilderConfiguration)
          .region(region)               
          .build();
  
          try {
              // Create a CopyObjectRequest object.
              CopyObjectRequest copyObjectRequest = new CopyObjectRequest(sourceBucketName, sourceKey, destinationBucketName, destinationKey);
  
              // Set new file metadata.
              ObjectMetadata meta = new ObjectMetadata();
              meta.setContentType("text/plain");
              // Specify whether to overwrite the destination object if it has the same name. In this example, this parameter is set to true, which indicates that the destination object cannot be overwritten.
              // meta.setHeader("x-oss-forbid-overwrite", "true");
              // Specify the source address for the copy operation.
              // meta.setHeader(OSSHeaders.COPY_OBJECT_SOURCE, "/examplebucket/recode-test.txt");
              // If the ETag of the source object matches the specified ETag, the copy operation is performed and 200 OK is returned.
              // meta.setHeader(OSSHeaders.COPY_OBJECT_SOURCE_IF_MATCH, "5B3C1A2E053D763E1B002CC607C5****");
              // If the ETag of the source object does not match the specified ETag, the copy operation is performed and 200 OK is returned.
              // meta.setHeader(OSSHeaders.COPY_OBJECT_SOURCE_IF_NONE_MATCH, "5B3C1A2E053D763E1B002CC607C5****");
              // If the specified time is the same as or later than the actual modification time of the object, the object is copied and 200 OK is returned.
              // meta.setHeader(OSSHeaders.COPY_OBJECT_SOURCE_IF_UNMODIFIED_SINCE, "2021-12-09T07:01:56.000Z");
              // If the source object has been modified after the specified time, the copy operation is performed.
              // meta.setHeader(OSSHeaders.COPY_OBJECT_SOURCE_IF_MODIFIED_SINCE, "2021-12-09T07:01:56.000Z");
              // Specify how to set the metadata of the destination object. In this example, this parameter is set to COPY, which indicates that the metadata of the source object is copied to the destination object.
              // meta.setHeader(OSSHeaders.COPY_OBJECT_METADATA_DIRECTIVE, "COPY");
              // Specify the server-side encryption algorithm that OSS uses to create the destination object.
              // meta.setHeader(OSSHeaders.OSS_SERVER_SIDE_ENCRYPTION, ObjectMetadata.KMS_SERVER_SIDE_ENCRYPTION);
              // The customer master key (CMK) managed by KMS. This parameter is valid only when x-oss-server-side-encryption is set to KMS.
              // meta.setHeader(OSSHeaders.OSS_SERVER_SIDE_ENCRYPTION_KEY_ID, "9468da86-3509-4f8d-a61e-6eab1eac****");
              // Specify the access permissions for the destination object when it is created in OSS. In this example, this parameter is set to Private, which indicates that only the object owner and authorized users have read and write permissions. Other users cannot access the object.
              // meta.setHeader(OSSHeaders.OSS_OBJECT_ACL, CannedAccessControlList.Private);
              // Specify the storage class of the object. In this example, this parameter is set to Standard.
              // meta.setHeader(OSSHeaders.OSS_STORAGE_CLASS, StorageClass.Standard);
              // Specify the tags for the object. You can specify multiple tags.
              // meta.setHeader(OSSHeaders.OSS_TAGGING, "a:1");
              // Specify how to set the tags for the destination object. In this example, this parameter is set to COPY, which indicates that the tags of the source object are copied to the destination object.
              // meta.setHeader(OSSHeaders.COPY_OBJECT_TAGGING_DIRECTIVE, "COPY");
              copyObjectRequest.setNewObjectMetadata(meta);
  
              // Copy the file.
              CopyObjectResult result = ossClient.copyObject(copyObjectRequest);
              System.out.println("ETag: " + result.getETag() + " LastModified: " + result.getLastModified());
          } 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();
              }
          }
      }
  }                 

Copy large files

For objects larger than 1 GB, you can use multipart copy (UploadPartCopy). A multipart copy consists of three steps:

1. Initialize a multipart copy task by calling the ossClient.initiateMultipartUpload method.

2. Copy the parts by calling the ossClient.uploadPartCopy method. All parts except the last one must be larger than 100 KB.

3. Complete the multipart copy task by calling the ossClient.completeMultipartUpload method.

The following code provides an example of how to use multipart copy to copy the srcexampleobject.txt object from the srcexamplebucket bucket to the desexampleobject.txt object in the desexamplebucket bucket.

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.*;
import java.util.ArrayList;
import java.util.List;

public class Demo {
    public static void main(String[] args) throws Exception {
        // The endpoint of the China (Hangzhou) region is used as an example. For other regions, specify the actual endpoint.
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Obtain access credentials from environment variables. Before you run this code, ensure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set.
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the name of the source bucket.
        String sourceBucketName = "srcexamplebucket";
        // Specify the full path of the source object. The full path cannot include the bucket name.
        String sourceKey = "srcexampleobject.txt";
        // Specify the name of the destination bucket. The destination bucket must be in the same region as the source bucket.
        String destinationBucketName = "desexamplebucket";
        // Specify the full path of the destination object. The full path cannot include the bucket name.
        String destinationKey = "desexampleobject.txt";
        // Specify the region where the bucket is located. This example uses the China (Hangzhou) region. Set Region to cn-hangzhou.
        String region = "cn-hangzhou";

        // Create an OSSClient instance.
        // When the OSSClient instance is no longer needed, call the shutdown method to release resources.
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);        
        OSS ossClient = OSSClientBuilder.create()
        .endpoint(endpoint)
        .credentialsProvider(credentialsProvider)
        .clientConfiguration(clientBuilderConfiguration)
        .region(region)               
        .build();

        try {
            ObjectMetadata objectMetadata = ossClient.getObjectMetadata(sourceBucketName, sourceKey);
            // Get the size of the file to be copied.
            long contentLength = objectMetadata.getContentLength();

            // Set the part size to 10 MB. The unit is bytes.
            long partSize = 1024 * 1024 * 10;

            // Calculate the total number of parts.
            int partCount = (int) (contentLength / partSize);
            if (contentLength % partSize != 0) {
                partCount++;
            }
            System.out.println("total part count:" + partCount);

            // Initialize the copy task. You can use InitiateMultipartUploadRequest to specify the metadata of the destination object.
            InitiateMultipartUploadRequest initiateMultipartUploadRequest = new InitiateMultipartUploadRequest(destinationBucketName, destinationKey);
            // Copy the ContentType and UserMetadata of the source file. By default, multipart copy does not copy them.
            ObjectMetadata metadata = new ObjectMetadata();
            metadata.setContentType(objectMetadata.getContentType());
            metadata.setUserMetadata(objectMetadata.getUserMetadata());
            initiateMultipartUploadRequest.setObjectMetadata(metadata);
            InitiateMultipartUploadResult initiateMultipartUploadResult = ossClient.initiateMultipartUpload(initiateMultipartUploadRequest);
            String uploadId = initiateMultipartUploadResult.getUploadId();

            // Copy parts.
            List<PartETag> partETags = new ArrayList<PartETag>();
            for (int i = 0; i < partCount; i++) {
                // Calculate the size of each part.
                long skipBytes = partSize * i;
                long size = partSize < contentLength - skipBytes ? partSize : contentLength - skipBytes;

                // Create an UploadPartCopyRequest. You can use UploadPartCopyRequest to specify conditions.
                UploadPartCopyRequest uploadPartCopyRequest =
                        new UploadPartCopyRequest(sourceBucketName, sourceKey, destinationBucketName, destinationKey);
                uploadPartCopyRequest.setUploadId(uploadId);
                uploadPartCopyRequest.setPartSize(size);
                uploadPartCopyRequest.setBeginIndex(skipBytes);
                uploadPartCopyRequest.setPartNumber(i + 1);
                //Map headers = new HashMap();
                // Specify the source address for the copy operation.
                // headers.put(OSSHeaders.COPY_OBJECT_SOURCE, "/examplebucket/desexampleobject.txt");
                // Specify the copy range of the source object. For example, set bytes=0-1023 to copy the first 1024 bytes.
                // headers.put(OSSHeaders.COPY_SOURCE_RANGE, "bytes=0-1023");
                // If the ETag of the source object matches the ETag that you provide, the copy operation is performed and 200 OK is returned.
                // headers.put(OSSHeaders.COPY_OBJECT_SOURCE_IF_MATCH, "5B3C1A2E053D763E1B002CC607C5****");
                // If the ETag of the source object does not match the ETag that you provide, the copy operation is performed and 200 OK is returned.
                // headers.put(OSSHeaders.COPY_OBJECT_SOURCE_IF_NONE_MATCH, "5B3C1A2E053D763E1B002CC607C5****");
                // If the specified time is the same as or later than the actual modification time of the file, the file is copied and 200 OK is returned.
                // headers.put(OSSHeaders.COPY_OBJECT_SOURCE_IF_UNMODIFIED_SINCE, "2021-12-09T07:01:56.000Z");
                // If the source object has been modified after the time that you specified, the copy operation is performed.
                // headers.put(OSSHeaders.COPY_OBJECT_SOURCE_IF_MODIFIED_SINCE, "2021-12-09T07:01:56.000Z");
                // uploadPartCopyRequest.setHeaders(headers);
                UploadPartCopyResult uploadPartCopyResult = ossClient.uploadPartCopy(uploadPartCopyRequest);

                // Save the returned ETag of the part to partETags.
                partETags.add(uploadPartCopyResult.getPartETag());
            }

            // Complete the multipart copy task.
            CompleteMultipartUploadRequest completeMultipartUploadRequest = new CompleteMultipartUploadRequest(
                    destinationBucketName, destinationKey, uploadId, partETags);
            ossClient.completeMultipartUpload(completeMultipartUploadRequest);
        } 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();
            }
        }
    }
}

References

• Copy a small object

  For more information about the API operation for copying small objects, see CopyObject.

• Copy large objects

  • For a complete code example of copying large objects, see the GitHub example.

  • For more information about the API operation for copying large objects, see UploadPartCopy.