deleteObjects using AWS SDK V2?

Question

I'm trying to migrate from AWS SDK V1.x to V2.2. I can't figure out the deleteObjects method though. I've found a bunch of examples - all the same one :-( that doesn't appear to ever use the list of objects to delete (i.e. the list is present, but never set in the DeleteObjectsRequest object - I assume that is where it should be set, but don't see where). How/where do I provide the object list? The examples I find are:

    System.out.println("Deleting objects from S3 bucket: " + bucket_name);
    for (String k : object_keys) {
        System.out.println(" * " + k);
    }

    Region region = Region.US_WEST_2;
    S3Client s3 = S3Client.builder().region(region).build();
    try {
        DeleteObjectsRequest dor = DeleteObjectsRequest.builder()
                .bucket(bucket_name)
                .build();
        s3.deleteObjects(dor);
    } catch (S3Exception e) {
        System.err.println(e.awsErrorDetails().errorMessage());
        System.exit(1);
    }

Answer 1

The previously accepted answer was very helpful even though it wasn't 100% complete. I used it to write the following method. It basically works though I haven't tested its error handling particularly well.

• An array of String keys is passed in, which are converted into the array of
  ObjectIdentifier's that deleteObjects requires.
• s3Client and log are assumed to have been initialized elsewhere. Feel free to remove the logging if you don't need it.

• The method currently returns the number of successfully deletes.

  public int deleteS3Objects(String bucketName, String[] keys) {
  
  List<ObjectIdentifier> objIds = Arrays.stream(keys)
          .map(key -> ObjectIdentifier.builder().key(key).build())
          .collect(Collectors.toList());
  try {
      DeleteObjectsRequest dor = DeleteObjectsRequest.builder()
              .bucket(bucketName)
              .delete(Delete.builder().objects(objIds).build())
              .build();
  
      DeleteObjectsResponse delResp = s3client.deleteObjects(dor);
  
      if (delResp.errors().size() > 0) {
          String err = String.format("%d errors returned while deleting %d objects",
                  delResp.errors().size(), objIds.size());
          log.warn(err);
      }
      if (delResp.deleted().size() < objIds.size()) {
          String err = String.format("%d of %d objects deleted",
                  delResp.deleted().size(), objIds.size());
          log.warn(err);
      }
      return delResp.deleted().size();
  }
  catch(AwsServiceException e) {
      // The call was transmitted successfully, but Amazon S3 couldn't process 
      // it, so it returned an error response.
      log.error("Error received from S3 while attempting to delete objects", e);
  }
  catch(SdkClientException e) {
      // Amazon S3 couldn't be contacted for a response, or the client
      // couldn't parse the response from Amazon S3.
      log.error("Exception occurred while attempting to delete objects from S3", e);
  }
  return 0;
  }
  

(Gratuitous commentary: I find it odd that in AWS SDK v2.3.9, deleteObjects requires Delete.Builder and ObjectIdentifier keys but getObject and putObject accept String keys. Why doesn't DeleteObjectsRequest.Builder just have a keys() method? They haven't officially said the SDK is production-ready AFAIK so some of this may be subject to change.)

Answer 2

Looks some more objects are needed to assign the key of the object in s3. This is untested, I put the links to the methods at the end.

System.out.println("Deleting objects from S3 bucket: " + bucket_name);

for (String k : object_keys) {
    System.out.println(" * " + k);
}

Region region = Region.US_WEST_2;
S3Client s3 = S3Client.builder().region(region).build();

try {

   ObjectIdentifier objectToDelete = ObjectIdentifier.Builder()
            .key(KEY_OBJECT_TO_DELETE);

   Delete delete_me Delete.Builder.objects(objectToDelete) 

   DeleteObjectsRequest dor = DeleteObjectsRequest.builder()
            .bucket(bucket_name)
            .delete(delete_me)
            .build();

    s3.deleteObjects(dor);

} catch (S3Exception e) {
    System.err.println(e.awsErrorDetails().errorMessage());
    System.exit(1);
}

Key to delete https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/s3/model/ObjectIdentifier.html#key--

Delete object https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/s3/model/ObjectIdentifier.Builder.html