How do I expose data in a JSON format through a web service using Java?

Question

Is there an easy way to return data to web service clients in JSON using java? I\'m fine with servlets, spring, etc.

Answer 1

As already mentioned, Jersey (JAX-RS impl) is the framework to use; but for basic mapping of Java objects to/from JSON, Tutorial is good. Unlike many alternatives, it does not use strange XML-compatibility conventions but reads and writes clean JSON that directly maps to and from objects. It also has no problems with null (there is difference between missing entry and one having null), empty Lists or Strings (both are distinct from nulls).

Jackson works nicely with Jersey as well, either using JAX-RS provider jar, or even just manually. Similarly it's trivially easy to use with plain old servlets; just get input/output stream, call ObjectMapper.readValue() and .writeValue(), and that's about it.