Spring 启动 Rest Controller 如何返回不同的 Z293C9EA246FF9985DC6F62A650F788 状态码？

Question

I am using Spring Boot for a simple REST API and would like to return a correct HTTP statuscode if something fails.

@RequestMapping(value="/rawdata/", method = RequestMethod.PUT)
@ResponseBody
@ResponseStatus( HttpStatus.OK )
public RestModel create(@RequestBody String data) {
    // code ommitted..
    // how do i return a correct status code if something fails?
}

Being new to Spring and Spring Boot, the basic question is how do i return different status codes when something is ok or fails?

Answer 1

There are several options you can use. Quite good way is to use exceptions and class for handling called @ControllerAdvice :

@ControllerAdvice
class GlobalControllerExceptionHandler {
    @ResponseStatus(HttpStatus.CONFLICT)  // 409
    @ExceptionHandler(DataIntegrityViolationException.class)
    public void handleConflict() {
        // Nothing to do
    }
}

Also you can pass HttpServletResponse to controller method and just set response code:

public RestModel create(@RequestBody String data, HttpServletResponse response) {
    // response committed...
    response.setStatus(HttpServletResponse.SC_ACCEPTED);
}

Please refer to the this great blog post for details: Exception Handling in Spring MVC

---

NOTE

In Spring MVC using @ResponseBody annotation is redundant - it's already included in @RestController annotation.

Answer 2

One of the way to do this is you can use ResponseEntity as a return object.

@RequestMapping(value="/rawdata/", method = RequestMethod.PUT)

public ResponseEntity<?> create(@RequestBody String data) {
    if(everything_fine) {
        return new ResponseEntity<>(RestModel, HttpStatus.OK);
    } else {
        return new ResponseEntity<>(null, HttpStatus.INTERNAL_SERVER_ERROR);
    }
}

Answer 3

A nice way is to use Spring's ResponseStatusException

Rather than returning a ResponseEntity or similar you simply throw the ResponseStatusException from the controller with an HttpStatus and cause, for example:

throw new ResponseStatusException(HttpStatus.BAD_REQUEST, "Cause description here");

This results in a response to the client containing the HTTP status:

{
  "timestamp": "2020-07-09T04:43:04.695+0000",
  "status": 400,
  "error": "Bad Request",
  "message": "Cause description here",
  "path": "/test-api/v1/search"
}

Note : HttpStatus provides many different status codes for your convenience.

Answer 4

In case you want to return a custom defined status code, you can use the ResponseEntity as here:

@RequestMapping(value="/rawdata/", method = RequestMethod.PUT)
public ResponseEntity<?> create(@RequestBody String data) {
    int customHttpStatusValue = 499;
    Foo foo = bar();
    return ResponseEntity.status(customHttpStatusValue).body(foo);
}

The CustomHttpStatusValue could be any integer within or outside of standard HTTP Status Codes.

Answer 5

Try this code:

@RequestMapping(value = "/validate", method = RequestMethod.GET, produces = "application/json")
public ResponseEntity<ErrorBean> validateUser(@QueryParam("jsonInput") final String jsonInput) {
    int numberHTTPDesired = 400;
    ErrorBean responseBean = new ErrorBean();
    responseBean.setError("ERROR");
    responseBean.setMensaje("Error in validation!");

    return new ResponseEntity<ErrorBean>(responseBean, HttpStatus.valueOf(numberHTTPDesired));
}

Answer 6

There are different ways to return status code, 1 : RestController class should extends BaseRest class, in BaseRest class we can handle exception and return expected error codes. for example :

@RestController
@RequestMapping
class RestController extends BaseRest{

}

@ControllerAdvice
public class BaseRest {
@ExceptionHandler({Exception.class,...})
    @ResponseStatus(value=HttpStatus.INTERNAL_SERVER_ERROR)
    public ErrorModel genericError(HttpServletRequest request, 
            HttpServletResponse response, Exception exception) {
        
        ErrorModel error = new ErrorModel();
        resource.addError("error code", exception.getLocalizedMessage());
        return error;
    }

Answer 7

I think the easiest way is to make return type of your method as

ResponseEntity<WHATEVER YOU WANT TO RETURN>

and for sending any status code, just add return statement as

return ResponseEntity.status(HTTP STATUS).build();

For example, if you want to return a list of books,

public ResponseEntity<List<books>> getBooks(){

  List<books> list = this.bookService.getAllBooks();
  
  if(list.size() <= 0)
     return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
  else
     return ResponseEntity.of(Optional.of(list));

}