After you configure tags for an object, you can query the tags of the object. If versioning is enabled for a bucket that stores the object whose tags you want to query, Object Storage Service (OSS) returns the tags of the current version of the object by default. To query the tags of a specified version of the object, you must specify the version ID of the object.

Query the tags of an object

If versioning is not enabled for the bucket that stores the object whose tags you want to query, you can query the tags of the object based on your requirements. If versioning is enabled for the bucket that stores the object whose tags you want to query, OSS returns the tags of the current version of the object by default.

The following code provides an example on how to query the tags of the exampleobject.txt object in the exampledir directory of the examplebucket bucket:

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.*;
import java.util.*;

public class Demo {
    public static void main(String[] args) throws Throwable {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify the actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to access OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
        String accessKeyId = "yourAccessKeyId";
        String accessKeySecret = "yourAccessKeySecret";
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. Example: exampledir/exampleobject.txt. The full path of the object cannot contain the bucket name. 
        String objectName = "exampledir/exampleobject.txt";

        // Create an OSSClient instance. 
        OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);

        try {
            // Query the tags of the object. 
            TagSet tagSet = ossClient.getObjectTagging(bucketName, objectName);
            Map<String, String> tags = tagSet.getAllTags();

            // View the tags of the object. 
            System.out.println("object tagging: "+ tags.toString());
        } 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();
            }
        }
    }
}

Query the tags of a specified version of an object

If versioning is enabled for the bucket that stores the object whose tags you want to query, you can query the tags of a specified version of the object by specifying the version ID of the object.

The following code provides an example on how to query the tags of a specified version of the exampleobject.txt object in the exampledir directory of the examplebucket bucket:

Note For more information about how to query the version IDs of an object, see List objects.
import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
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 Throwable {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify the actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to access OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
        String accessKeyId = "yourAccessKeyId";
        String accessKeySecret = "yourAccessKeySecret";
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. Example: exampledir/exampleobject.txt. The full path of the object cannot contain the bucket name. 
        String objectName = "exampledir/exampleobject.txt";
        // Specify the version ID of the object. Example: CAEQMxiBgICAof2D0BYiIDJhMGE3N2M1YTI1NDQzOGY5NTkyNTI3MGYyMzJm****. 
        String versionId = "CAEQMxiBgICAof2D0BYiIDJhMGE3N2M1YTI1NDQzOGY5NTkyNTI3MGYyMzJm****";

        // Create an OSSClient instance. 
        OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);

        try {
            GenericRequest genericRequest = new GenericRequest(bucketName, objectName, versionId);
            TagSet tagSet = ossClient.getObjectTagging(genericRequest);

            // View the tags of the object. 
            System.out.println("object tagging: "+ tagSet.toString());
        } 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

  • For more information about the complete sample code that is used to query the tags of an object, visit GitHub.
  • For more information about the API operation that you can call to query the tags of an object, see GetObjectTagging.