What is the difference between ResponseEntity<T> and @ResponseBody?
I have a simple handler in my controller which returns a message
@RequestMapping(value = "/message")
@ResponseBody
public Message get() {
return new Message(penguinCounter.incrementAndGet() + " penguin!");
}
At the same time I can use something like this
@RequestMapping(value = "/message")
ResponseEntity<Message> get() {
Message message = new Message(penguinCounter.incrementAndGet() + " penguin!");
return new ResponseEntity<Message>(message, HttpStatus.OK);
}
What is the difference betweet this two approaches? Let's not take into account HttpStatus :)
ResponseEntity will give you some added flexibility in defining arbitrary HTTP response headers. See the 4th constructor here:
http://docs.spring.io/spring/docs/3.0.x/api/org/springframework/http/ResponseEntity.html
ResponseEntity(T body, MultiValueMap<String,String> headers, HttpStatus statusCode)
A List of possible HTTP response headers is available here:
http://en.wikipedia.org/wiki/List_of_HTTP_header_fields#Responses
Some commonly-used ones are Status, Content-Type and Cache-Control.
If you don't need that, using @ResponseBody will be a tiny bit more concise.
HttpEntity represents an HTTP request or response consists of headers and body.
// Only talks about body & headers, but doesn't talk about status code
public HttpEntity(T body, MultiValueMap<String,String> headers)
ResponseEntity extends HttpEntity but also adds a Http status code.
// i.e ResponseEntity = HttpEntity + StatusCode
public ResponseEntity(T body, MultiValueMap<String,String> headers, HttpStatus statusCode)
Hence used to fully configure the HTTP response.
For Ex:
@ControllerAdvice
public class JavaWebExeptionHandler {
@Autowired
ExceptionErrorCodeMap exceptionErrorCodeMap;
@ExceptionHandler(RuntimeException.class)
public final ResponseEntity<ExceptionResponseBody> handleAllExceptions(Exception ex) {
Integer expCode = exceptionErrorCodeMap.getExpCode(ex.getClass());
// We have not added headers to response here, If you want you can add by using respective constructor
return new ResponseEntity<ExceptionResponseBody>(new ExceptionResponseBody(expCode, ex.getMessage()),
HttpStatus.valueOf(expCode));
}
}
@ResponseBody indicates that return value of method on which it is used is bound to the response body (Mean the return value of method is treated as Http response body)