spring mvc @ResponseStatus 和 ResponseEntity

た入场券 2022-06-16 04:47 200阅读 0赞

@ResponseStatus 是标记一个方法或异常类在返回时响应的http状态。其代码注释如下：

*
 * The status code is applied to the HTTP response when the handler
 * method is invoked and overrides status information set by other means,
 * like {
 @code ResponseEntity} or {
 @code "redirect:"}.
 *
 * Warning: when using this annotation on an exception
 * class, or when setting the {
 @code reason} attribute of this annotation,
 * the {
 @code HttpServletResponse.sendError} method will be used.
 *
 * With {
 @code HttpServletResponse.sendError}, the response is considered
 * complete and should not be written to any further. Furthermore, the Servlet
 * container will typically write an HTML error page therefore making the
 * use of a {
 @code reason} unsuitable for REST APIs. For such cases it is
 * preferable to use a {
 @link org.springframework.http.ResponseEntity} as
 * a return type and avoid the use of {
 @code @ResponseStatus} altogether.
 *
 * Note that a controller class may also be annotated with
 * {
 @code @ResponseStatus} and is then inherited by all {
 @code @RequestMapping}
 * methods.

@ResponseStatus 可以结合 @ResponseBody 一起使用。

@RequestMapping("/testResponseBody")
 @ResponseBody
 public Map<String, String> testResponseBody(){
 return ImmutableMap.of("key", "value");
 }
 
 
 @RequestMapping("/testResponseBodyFaild")
 @ResponseBody
 @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
 public Map<String, String> testResponseBodyFaild(){
 return ImmutableMap.of("key", "faild");
 }

这两个handler method返回的http status code(http状态码) 分别是200 和 501。

ResponseEntity 是在 org.springframework.http.HttpEntity 的基础上添加了http status code(http状态码)，用于RestTemplate以及@Controller的HandlerMethod。它在Controoler中或者用于服务端响应时，作用是和@ResponseStatus与@ResponseBody结合起来的功能一样的。用于RestTemplate时，它是接收服务端返回的http status code 和 reason的。  
代码注释如下：

* Extension of {@link HttpEntity} that adds a {@link HttpStatus} status code.
 * Used in {@code RestTemplate} as well {@code @Controller} methods.
 *
 * In {@code RestTemplate}, this class is returned by
 * {@link org.springframework.web.client.RestTemplate#getForEntity getForEntity()} and
 * {@link org.springframework.web.client.RestTemplate#exchange exchange()}:
 * <pre class="code">
 * ResponseEntity<String> entity = template.getForEntity("http://example.com", String.class);
 * String body = entity.getBody();
 * MediaType contentType = entity.getHeaders().getContentType();
 * HttpStatus statusCode = entity.getStatusCode();
 * </pre>
 *
 * Can also be used in Spring MVC, as the return value from a @Controller method:
 * <pre class="code">
 * @RequestMapping("/handle")
 * public ResponseEntity<String> handle() {
 * URI location = ...;
 * HttpHeaders responseHeaders = new HttpHeaders();
 * responseHeaders.setLocation(location);
 * responseHeaders.set("MyResponseHeader", "MyValue");
 * return new ResponseEntity<String>("Hello World", responseHeaders, HttpStatus.CREATED);
 * }
 * </pre>
 * Or, by using a builder accessible via static methods:
 * <pre class="code">
 * @RequestMapping("/handle")
 * public ResponseEntity<String> handle() {
 * URI location = ...;
 * return ResponseEntity.created(location).header("MyResponseHeader", "MyValue").body("Hello World");
 * }
 * </pre>

ResponseEntity 和 @ResponseStatus 一起使用是无效的

@RequestMapping("/testResponseEntity")
 public ResponseEntity<Map<String, String>> testResponseEntity(){
 Map<String, String> map = ImmutableMap.of("key", "value");
 return ResponseEntity.ok(map);
 }
 
 @RequestMapping("/testResponseEntityFaild")
 @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
 public ResponseEntity<Map<String, String>> testResponseEntityFaild(){
 Map<String, String> map = ImmutableMap.of("key", "faild");
 return ResponseEntity.ok(map);
 }
 
 
 @RequestMapping("/testResponseEntityFaild2")
 public ResponseEntity<Map<String, String>> testResponseEntityFaild2(){
 return ResponseEntity.badRequest().body(ImmutableMap.of("key", "faild"));
 }

这三个handler method返回的http status code(http状态码) 分别是200 、 200 和 400。

完整的TestController代码

import com.google.common.collect.ImmutableMap;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.bind.annotation.RestController;
 
 import java.util.Map;
 
 /** * Created by saleson on 2017/5/5. */
 @RestController
 @RequestMapping("/test")
 public class TestController { 
 
 @RequestMapping("/testResponseEntity")
 public ResponseEntity<Map<String, String>> testResponseEntity(){
 Map<String, String> map = ImmutableMap.of("key", "value");
 return ResponseEntity.ok(map);
 }
 
 @RequestMapping("/testResponseEntityFaild")
 @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
 public ResponseEntity<Map<String, String>> testResponseEntityFaild(){
 Map<String, String> map = ImmutableMap.of("key", "faild");
 return ResponseEntity.ok(map);
 }
 
 
 @RequestMapping("/testResponseEntityFaild2")
 public ResponseEntity<Map<String, String>> testResponseEntityFaild2(){
 return ResponseEntity.badRequest().body(ImmutableMap.of("key", "faild"));
 }
 
 
 @RequestMapping("/testResponseBody")
 @ResponseBody
 public Map<String, String> testResponseBody(){
 return ImmutableMap.of("key", "value");
 }
 
 @RequestMapping("/testResponseBodyFaild")
 @ResponseBody
 @ResponseStatus(HttpStatus.NOT_IMPLEMENTED)
 public Map<String, String> testResponseBodyFaild(){
 return ImmutableMap.of("key", "faild");
 }
 }

返回的http status code截图:

![这里写图片描述][SouthEast]

[SouthEast]: /images/20220616/7f3b9ffa2d7246e89cca89c5fe4ba823.png