DeletingMultipleObjectsUsingJava.md

Deleting multiple objects using the AWS SDK for Java

The AWS SDK for Java provides the AmazonS3Client.deleteObjects() method for deleting multiple objects. For each object that you want to delete, you specify the key name. If the bucket is versioning-enabled, you have the following options:

• Specify only the object's key name. Amazon S3 will add a delete marker to the object.

• Specify both the object's key name and a version ID to be deleted. Amazon S3 will delete the specified version of the object.

Example The following example uses the Multi-Object Delete API to delete objects from a bucket that is not version-enabled. The example uploads sample objects to the bucket and then uses the AmazonS3Client.deleteObjects() method to delete the objects in a single request. In the DeleteObjectsRequest, the example specifies only the object key names because the objects do not have version IDs. For more information about deleting objects, see Deleting objects. For instructions on creating and testing a working sample, see Testing the Amazon S3 Java Code Examples.

import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.DeleteObjectsRequest;
import com.amazonaws.services.s3.model.DeleteObjectsRequest.KeyVersion;
import com.amazonaws.services.s3.model.DeleteObjectsResult;

import java.io.IOException;
import java.util.ArrayList;

public class DeleteMultipleObjectsNonVersionedBucket {

    public static void main(String[] args) throws IOException {
        Regions clientRegion = Regions.DEFAULT_REGION;
        String bucketName = "*** Bucket name ***";

        try {
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                    .withRegion(clientRegion)
                    .build();

            // Upload three sample objects.
            ArrayList<KeyVersion> keys = new ArrayList<KeyVersion>();
            for (int i = 0; i < 3; i++) {
                String keyName = "delete object example " + i;
                s3Client.putObject(bucketName, keyName, "Object number " + i + " to be deleted.");
                keys.add(new KeyVersion(keyName));
            }
            System.out.println(keys.size() + " objects successfully created.");

            // Delete the sample objects.
            DeleteObjectsRequest multiObjectDeleteRequest = new DeleteObjectsRequest(bucketName)
                    .withKeys(keys)
                    .withQuiet(false);

            // Verify that the objects were deleted successfully.
            DeleteObjectsResult delObjRes = s3Client.deleteObjects(multiObjectDeleteRequest);
            int successfulDeletes = delObjRes.getDeletedObjects().size();
            System.out.println(successfulDeletes + " objects successfully deleted.");
        } catch (AmazonServiceException e) {
            // The call was transmitted successfully, but Amazon S3 couldn't process 
            // it, so it returned an error response.
            e.printStackTrace();
        } catch (SdkClientException e) {
            // Amazon S3 couldn't be contacted for a response, or the client
            // couldn't parse the response from Amazon S3.
            e.printStackTrace();
        }
    }
}

Example The following example uses the Multi-Object Delete API to delete objects from a version-enabled bucket. It does the following:

1. Creates sample objects and then deletes them, specifying the key name and version ID for each object to delete. The operation deletes only the specified object versions.

2. Creates sample objects and then deletes them by specifying only the key names. Because the example doesn't specify version IDs, the operation adds a delete marker to each object, without deleting any specific object versions. After the delete markers are added, these objects will not appear in the AWS Management Console.

3. Remove the delete markers by specifying the object keys and version IDs of the delete markers. The operation deletes the delete markers, which results in the objects reappearing in the AWS Management Console.

import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.BucketVersioningConfiguration;
import com.amazonaws.services.s3.model.DeleteObjectsRequest;
import com.amazonaws.services.s3.model.DeleteObjectsRequest.KeyVersion;
import com.amazonaws.services.s3.model.DeleteObjectsResult;
import com.amazonaws.services.s3.model.DeleteObjectsResult.DeletedObject;
import com.amazonaws.services.s3.model.PutObjectResult;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class DeleteMultipleObjectsVersionEnabledBucket {
    private static AmazonS3 S3_CLIENT;
    private static String VERSIONED_BUCKET_NAME;

    public static void main(String[] args) throws IOException {
        Regions clientRegion = Regions.DEFAULT_REGION;
        VERSIONED_BUCKET_NAME = "*** Bucket name ***";

        try {
            S3_CLIENT = AmazonS3ClientBuilder.standard()
                    .withCredentials(new ProfileCredentialsProvider())
                    .withRegion(clientRegion)
                    .build();

            // Check to make sure that the bucket is versioning-enabled.
            String bucketVersionStatus = S3_CLIENT.getBucketVersioningConfiguration(VERSIONED_BUCKET_NAME).getStatus();
            if (!bucketVersionStatus.equals(BucketVersioningConfiguration.ENABLED)) {
                System.out.printf("Bucket %s is not versioning-enabled.", VERSIONED_BUCKET_NAME);
            } else {
                // Upload and delete sample objects, using specific object versions.
                uploadAndDeleteObjectsWithVersions();

                // Upload and delete sample objects without specifying version IDs.
                // Amazon S3 creates a delete marker for each object rather than deleting
                // specific versions.
                DeleteObjectsResult unversionedDeleteResult = uploadAndDeleteObjectsWithoutVersions();

                // Remove the delete markers placed on objects in the non-versioned create/delete method.
                multiObjectVersionedDeleteRemoveDeleteMarkers(unversionedDeleteResult);
            }
        } catch (AmazonServiceException e) {
            // The call was transmitted successfully, but Amazon S3 couldn't process 
            // it, so it returned an error response.
            e.printStackTrace();
        } catch (SdkClientException e) {
            // Amazon S3 couldn't be contacted for a response, or the client
            // couldn't parse the response from Amazon S3.
            e.printStackTrace();
        }
    }

    private static void uploadAndDeleteObjectsWithVersions() {
        System.out.println("Uploading and deleting objects with versions specified.");

        // Upload three sample objects.
        ArrayList<KeyVersion> keys = new ArrayList<KeyVersion>();
        for (int i = 0; i < 3; i++) {
            String keyName = "delete object without version ID example " + i;
            PutObjectResult putResult = S3_CLIENT.putObject(VERSIONED_BUCKET_NAME, keyName,
                    "Object number " + i + " to be deleted.");
            // Gather the new object keys with version IDs.
            keys.add(new KeyVersion(keyName, putResult.getVersionId()));
        }

        // Delete the specified versions of the sample objects.
        DeleteObjectsRequest multiObjectDeleteRequest = new DeleteObjectsRequest(VERSIONED_BUCKET_NAME)
                .withKeys(keys)
                .withQuiet(false);

        // Verify that the object versions were successfully deleted.
        DeleteObjectsResult delObjRes = S3_CLIENT.deleteObjects(multiObjectDeleteRequest);
        int successfulDeletes = delObjRes.getDeletedObjects().size();
        System.out.println(successfulDeletes + " objects successfully deleted");
    }

    private static DeleteObjectsResult uploadAndDeleteObjectsWithoutVersions() {
        System.out.println("Uploading and deleting objects with no versions specified.");

        // Upload three sample objects.
        ArrayList<KeyVersion> keys = new ArrayList<KeyVersion>();
        for (int i = 0; i < 3; i++) {
            String keyName = "delete object with version ID example " + i;
            S3_CLIENT.putObject(VERSIONED_BUCKET_NAME, keyName, "Object number " + i + " to be deleted.");
            // Gather the new object keys without version IDs.
            keys.add(new KeyVersion(keyName));
        }

        // Delete the sample objects without specifying versions.
        DeleteObjectsRequest multiObjectDeleteRequest = new DeleteObjectsRequest(VERSIONED_BUCKET_NAME).withKeys(keys)
                .withQuiet(false);

        // Verify that delete markers were successfully added to the objects.
        DeleteObjectsResult delObjRes = S3_CLIENT.deleteObjects(multiObjectDeleteRequest);
        int successfulDeletes = delObjRes.getDeletedObjects().size();
        System.out.println(successfulDeletes + " objects successfully marked for deletion without versions.");
        return delObjRes;
    }

    private static void multiObjectVersionedDeleteRemoveDeleteMarkers(DeleteObjectsResult response) {
        List<KeyVersion> keyList = new ArrayList<KeyVersion>();
        for (DeletedObject deletedObject : response.getDeletedObjects()) {
            // Note that the specified version ID is the version ID for the delete marker.
            keyList.add(new KeyVersion(deletedObject.getKey(), deletedObject.getDeleteMarkerVersionId()));
        }
        // Create a request to delete the delete markers.
        DeleteObjectsRequest deleteRequest = new DeleteObjectsRequest(VERSIONED_BUCKET_NAME).withKeys(keyList);

        // Delete the delete markers, leaving the objects intact in the bucket.
        DeleteObjectsResult delObjRes = S3_CLIENT.deleteObjects(deleteRequest);
        int successfulDeletes = delObjRes.getDeletedObjects().size();
        System.out.println(successfulDeletes + " delete markers successfully deleted");
    }
}