Spring MVC, deserialize single JSON?

Question

How can I easily separate JSON values that are sent in the same request?

Given that I POST a JSON to my server:

{\"first\":\"A\",\"second\":\"B\"}
<         


        

Answer 1

I have written a custom WebArgumentResolver that does exactly this, combined with a custom annotation.

I don't have the source available to me now, but basically I annotated my method like this:

@RequestMapping(value = "/path", method = RequestMethod.POST)
public void handleRequest(@JsonField("first") String first, @JsonField("second") String second) { 
    // ...
}

Then my JsonFieldWebArgumentResolver checks if the method parameter is annotated with JsonField, and if it is it extracts the actual type from the parameter (not quite straight-forward it turns out if you want to handle generic parameters as well, such as List<String> or List<Pojo>), and invokes Jackson's JsonParser manually to create the correct type. It's a shame I can't show you any code, but that's the gist of it.

However, that solution is for Spring MVC 3.0, and if you are using 3.1 I think you will be better off using a custom HandlerMethodArgumentResolver instead. But the idea should be the same.

Answer 2

POJO

public class Input {
    private String first;
    private String second;

    //getters/setters
}

...and then:

public void handleRequest(@RequestBody Input input)

In this case you need Jackson to be available on the CLASSPATH.

Map

public void handleRequest(@RequestBody Map<String, String> input)