为Spring RESTful应用程序使用ResponseEntity <T>和@RestController时

Question

我正在使用Spring Framework 4.0.7,以及MVC和Rest

我可以和平地工作:

• @Controller
• ResponseEntity<T>

例如:

@Controller
@RequestMapping("/person")
@Profile("responseentity")
public class PersonRestResponseEntityController {

用这个方法(只是为了创建)

@RequestMapping(value="/", method=RequestMethod.POST)
public ResponseEntity<Void> createPerson(@RequestBody Person person, UriComponentsBuilder ucb){
    logger.info("PersonRestResponseEntityController  - createPerson");
    if(person==null)
        logger.error("person is null!!!");
    else
        logger.info("{}", person.toString());

    personMapRepository.savePerson(person);
    HttpHeaders headers = new HttpHeaders();
    headers.add("1", "uno");
    //http://localhost:8080/spring-utility/person/1
    headers.setLocation(ucb.path("/person/{id}").buildAndExpand(person.getId()).toUri());

    return new ResponseEntity<>(headers, HttpStatus.CREATED);
}

返回一些东西

@RequestMapping(value="/{id}", method=RequestMethod.GET)
public ResponseEntity<Person> getPerson(@PathVariable Integer id){
    logger.info("PersonRestResponseEntityController  - getPerson - id: {}", id);
    Person person = personMapRepository.findPerson(id);
    return new ResponseEntity<>(person, HttpStatus.FOUND);
}

工作良好

我可以这样做:

• @RestController(我知道它与@Controller+ 相同@ResponseBody)
• @ResponseStatus

例如:

@RestController
@RequestMapping("/person")
@Profile("restcontroller")
public class PersonRestController {

用这个方法(只是为了创建)

@RequestMapping(value="/", method=RequestMethod.POST)
@ResponseStatus(HttpStatus.CREATED)
public void createPerson(@RequestBody Person person, HttpServletRequest request, HttpServletResponse response){
    logger.info("PersonRestController  - createPerson");
    if(person==null)
        logger.error("person is null!!!");
    else
        logger.info("{}", person.toString());

    personMapRepository.savePerson(person);
    response.setHeader("1", "uno");

    //http://localhost:8080/spring-utility/person/1
    response.setHeader("Location", request.getRequestURL().append(person.getId()).toString());
}

返回一些东西

@RequestMapping(value="/{id}", method=RequestMethod.GET)
@ResponseStatus(HttpStatus.FOUND)
public Person getPerson(@PathVariable Integer id){
    logger.info("PersonRestController  - getPerson - id: {}", id);
    Person person = personMapRepository.findPerson(id);
    return person;
}

我的问题是:

1. 当有充分理由或具体情况时,必须强制使用另一个选项
2. 如果(1)无关紧要,建议采用何种方法以及原因.

Answer 1

ResponseEntity用于表示整个HTTP响应.您可以控制进入它的任何内容:状态代码,标题和正文.

@ResponseBody是HTTP响应主体的标记,并@ResponseStatus声明HTTP响应的状态代码.

@ResponseStatus不是很灵活.它标记整个方法,因此您必须确保您的处理程序方法始终以相同的方式运行.你仍然无法设置标题.你需要HttpServletResponse或一个HttpHeaders参数.

基本上,ResponseEntity让你做更多.

Answer 2

完成Sotorios Delimanolis的答案.

确实,它ResponseEntity为您提供了更大的灵活性,但在大多数情况下您不需要它,并且您最终会ResponseEntity在控制器中无处不在,因此难以阅读和理解.

如果要处理错误(未找到,冲突等)等特殊情况,可以HandlerExceptionResolver在Spring配置中添加.因此,在您的代码中,您只是抛出一个特定的异常(NotFoundException例如)并决定在Handler中做什么(将HTTP状态设置为404),使Controller代码更清晰.

Answer 3

根据官方文档:使用@RestController注释创建REST控制器

@RestController是一个结合@ResponseBody和@Controller的构造型注释.更重要的是,它为您的Controller提供了更多的意义,并且可能在框架的未来版本中带来额外的语义.

它似乎最好@RestController用于清晰度,但你也可以在需要时将它与ResponseEntity灵活性结合起来(根据官方教程和这里的代码以及我的问题来确认).

例如:

@RestController
public class MyController {

    @GetMapping(path = "/test")
    @ResponseStatus(HttpStatus.OK)
    public User test() {
        User user = new User();
        user.setName("Name 1");

        return user;
    }

}

是相同的:

@RestController
public class MyController {

    @GetMapping(path = "/test")
    public ResponseEntity<User> test() {
        User user = new User();
        user.setName("Name 1");

        HttpHeaders responseHeaders = new HttpHeaders();
        // ...
        return new ResponseEntity<>(user, responseHeaders, HttpStatus.OK);
    }

}

这样,您ResponseEntity只能在需要时定义.

更新

你可以用这个:

    return ResponseEntity.ok().headers(responseHeaders).body(user);

Answer 4

适当的REST API应该包含以下组件以作为响应

1. 状态码
2. 反应体
3. 更改资源的位置（例如，如果创建了资源，则客户将有兴趣知道该位置的URL）

ResponseEntity的主要目的是提供选项3，而没有ResponseEntity则可以实现其余选项。

因此，如果您想提供资源的位置，那么使用ResponseEntity会更好，否则可以避免。

考虑一个示例，其中修改了API以提供所有提到的选项

// Step 1 - Without any options provided
@RequestMapping(value="/{id}", method=RequestMethod.GET)
public @ResponseBody Spittle spittleById(@PathVariable long id) {
  return spittleRepository.findOne(id);
}

// Step 2- We need to handle exception scenarios, as step 1 only caters happy path.
@ExceptionHandler(SpittleNotFoundException.class)
@ResponseStatus(HttpStatus.NOT_FOUND)
public Error spittleNotFound(SpittleNotFoundException e) {
  long spittleId = e.getSpittleId();
  return new Error(4, "Spittle [" + spittleId + "] not found");
}

// Step 3 - Now we will alter the service method, **if you want to provide location**
@RequestMapping(
    method=RequestMethod.POST
    consumes="application/json")
public ResponseEntity<Spittle> saveSpittle(
    @RequestBody Spittle spittle,
    UriComponentsBuilder ucb) {

  Spittle spittle = spittleRepository.save(spittle);
  HttpHeaders headers = new HttpHeaders();
  URI locationUri =
  ucb.path("/spittles/")
      .path(String.valueOf(spittle.getId()))
      .build()
      .toUri();
  headers.setLocation(locationUri);
  ResponseEntity<Spittle> responseEntity =
      new ResponseEntity<Spittle>(
          spittle, headers, HttpStatus.CREATED)
  return responseEntity;
}

// Step4 - If you are not interested to provide the url location, you can omit ResponseEntity and go with
@RequestMapping(
    method=RequestMethod.POST
    consumes="application/json")
@ResponseStatus(HttpStatus.CREATED)
public Spittle saveSpittle(@RequestBody Spittle spittle) {
  return spittleRepository.save(spittle);
}

来源-行动中的春天