I am very new to Spring. I have a REST api written in Spring, but I don't know how to return a JSON response with a custom http response code.
I return a JSON response as follows:
public String getUser(String id){
...
return jsonObj;
}
But it always displays 200 http ok status code.
Here are my questions:
How can I synchronize the response JSON and HTTP code?
How is it possible to return JSON response and custom HTTP code in void function?
Use @ResponseStatus annotation:
@GetMapping
@ResponseStatus(HttpStatus.ACCEPTED)
public String getUser(String id) {...}
Alternative way: If you want to decide programmatically what status to return you can use ResponseEntity. Change return type of a method to ResponseEntity<String> and you'll be offered with a DSL like this:
ResponseEntity
.status(NOT_FOUND)
.contentType(TEXT_PLAIN)
.body("some body");
Here is how I do JSON returns from a Spring Handler method. My techniques are somewhat out-of-date, but are still reasonable.
Configure Jackson Add the following to the spring configuration xml file:
<bean name="jsonView"
class="org.springframework.web.servlet.view.json.MappingJackson2JsonView">
</bean>
With that, Spring will convert return values to JSON and place them in the body of the response.
Create a utility method to build the ResponseEntity
Odds are good that you will have multiple handler methods.
Instead of boilerplate code,
create a method to do the standard work.
ResponseEntity is a Spring class.
protected ResponseEntity<ResponseJson> buildResponse(
final ResponseJson jsonResponseBody,
final HttpStatus httpStatus)
{
final ResponseEntity<ResponseJson> returnValue;
if ((jsonResponseBody != null) &&
(httpStatus != null))
{
returnValue = new ResponseEntity<>(
jsonResponseBody,
httpStatus);
}
return returnValue;
}
Annotate the handler method
@RequestMapping(value = "/webServiceUri", method = RequestMethod.POST)
you can also use the @PostMethod annotation
@PostMethod("/webServiceUri")
Return ResponseEntity from the handler method
Call the utility method to build the ResponseEntity
public ResponseEntity<ResponseJson> handlerMethod(
... params)
{
... stuff
return buildResponse(json, httpStatus);
}
Annotate the handler parameters
Jackson will convert from json to the parameter type when you use the @RequestBody annotation.
public ResponseEntity<ResponseJson> handlerMethod(
final WebRequest webRequest,
@RequestBody final InputJson inputJson)
{
... stuff
}
You can use the @JsonView annotation.
Check out the Spring Reference for details about this.
Browse to the ref page and search for @JsonView.
