REST handler method response

Each REST handler method must send a response or throw an exception. The method may handle the response or allow the framework to convert the method return value to a JSON string. All responses are can be Content-Type specified as application/JSON. Though this is not mandatory, the handler method must handle the HTTP Content-Type header and response body.

String — If the type of object returned from the method is String, it is returned as-is with no validity checks. The method must ensure that the string is a properly formatted JSON encoded string.

ObjectNode — If the type of object returned from the method is ObjectNode, a part of Jackson JSON library, the framework serializes it and writes it back to the client.

Plain old Java object — If the type of object returned from the method is a Java object, the framework attempts to convert it to a JSON encoded string using the built-in Jackson library. If the object cannot be converted to a JSON encoded string, an HTTP 500 Internal Server Error is returned to the client, and the exception is recorded in the fathom error log file.

Note: Returning a string or an ObjectNode is quicker than returning a Java object because the latter avoids using reflection to serialize the object.

For details about Jackson capabilities, see https://github.com/FasterXML/jackson.

@RequestMapping(path = "/get", method = RequestMethod.GET)
public Object getSample(@QueryParam("id") String idFromQuery) {
return "{ \"id\" : \"someid\"}";
}

@RequestMapping(path = "/get", method = RequestMethod.GET)
public Object getSample(@QueryParam("id") String idFromQuery) {
    ObjectMapper mapper = new ObjectMapper();
    ObjectNode resp = mapper.createObjectNode();
    resp.put("id", "someid");

    return resp;
}

@RequestMapping(path = "/get", method = RequestMethod.GET)
public Object getSample(@QueryParam("id") String idFromQuery) {

    MyThing thing = new MyThing();
    thing.setId("someid");

    return thing;
}