AWS DynamoDB trigger using Lambda in JAVA

Question

I am trying to trigger an AWS lambda function written in Java, on dynamodb stream events. Amazon has a guide for the same, using NodeJS here http://docs.aws.amazon.com/lambd

Answer 1

To obtain the deserialized objects from event handler : 1) In the handler get json from input stream using something like this :

private String getJsonFrom(InputStream stream) throws IOException {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    int letter;
    while ((letter = stream.read()) != -1)
        baos.write(letter);

    return new String(baos.toByteArray());
}

2) Then create a specific deserializer derialize the object from json. 'NewImage' in case of DynamoDB event. One example here.