Operations, requests and responses changes - Amazon SDK for Java 2.x
Streaming operations
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Operations, requests and responses changes

In v2.x of the SDK for Java, requests are passed to a client operation. For example DynamoDbClient's PutItemRequest is passed to DynamoDbClient.putItem operation. These operations return a response from the Amazon Web Services service, such as a PutItemResponse.

Version 2.x of the SDK for Java has the following changes from 1.x.

  • Operations with multiple response pages now have a Paginator method for automatically iterating over all items in the response.

  • You cannot mutate requests and responses.

  • You must create requests and responses with a static builder method instead of a constructor. For example, 1.x's new PutItemRequest().withTableName(...) is now PutItemRequest.builder().tableName(...).build().

  • Operations support a short-hand way to create requests: dynamoDbClient.putItem(request -> request.tableName(...)).

Streaming operations

Streaming operations such as Amazon S3 getObject and putObject methods now support non-blocking I/O. As a result, the request and response POJOs no longer take an InputStream as a parameter. Instead, for synchronous requests the request object accepts RequestBody, which is a stream of bytes. The asynchronous equivalent accepts an AsyncRequestBody.

Example of Amazon S3 putObject operation in 1.x
s3client.putObject(BUCKET, KEY, new File(file_path));
Example of Amazon S3 putObject operation in 2.x
s3client.putObject(PutObjectRequest.builder()
                                 .bucket(BUCKET)
                                 .key(KEY)
                                 .build(),
                 RequestBody.of(Paths.get("myfile.in")));

In parallel, a streaming response object accepts a ResponseTransformer for synchronous clients and a AsyncResponseTransformer for asynchronous clients.

Example of Amazon S3 getObject operation in 1.x
S3Object o = s3.getObject(bucket, key);
S3ObjectInputStream s3is = o.getObjectContent();
FileOutputStream fos = new FileOutputStream(new File(key));
Example of Amazon S3 getObject operation in 2.x
s3client.getObject(GetObjectRequest.builder().bucket(bucket).key(key).build(),
		ResponseTransformer.toFile(Paths.get("key")));

In the SDK for Java 2.x , streaming response operations have an AsBytes method to load the response into memory and simplify common in-memory type conversions.