基本理念

第一个选项是定义错误对象并将其作为正文返回。如下所示：404 Not Found

Map<String, String> errors = ....;
return ResponseEntity.status(HttpStatus.NOT_FOUND).body(errors);

您可以抛出一个将解析为 .假设你有一个赞：ResponseEntityException404 Not FoundNotFoundException

@ResponseStatus(code = HttpStatus.NOT_FOUND)
public class NotFoundException extends RuntimeException {}

然后，如果在控制器中引发此异常，则会看到如下内容：

{  
   "timestamp":1461621047967,
   "status":404,
   "error":"Not Found",
   "exception":"NotFoundException",
   "message":"No message available",
   "path":"/greet"
}

如果要自定义消息和正文的其他部分，则应为 定义一个 。ExceptionHandlerNotFoundException

引入异常层次结构

如果您正在创建 RESTful API，并希望针对不同的例外情况使用不同的错误代码和错误消息，则可以创建表示这些情况的异常层次结构，并从每个情况中提取消息和代码。

例如，您可以引入一个异常，例如，它是控制器引发的所有其他异常的超类。此类定义一个代码/消息对，如下所示：APIException

public class APIException extends RuntimeException {
    private final int code;
    private final String message;

    APIException(int code, String message) {
        this.code = code;
        this.message = message;
    }

    public int code() {
        return code;
    }

    public String message() {
        return message;
    }
}

每个子类根据其异常的性质可以为该对提供一些合理的值。例如，我们可以有一个 ：InvalidStateException

@ResponseStatus(code = HttpStatus.BAD_REQUEST)
public class InvalidStateException extends APIException {
    public InvalidStateException() {
        super(1, "Application is in invalid state");
    }
}

或者那个臭名昭著的未找到的：

@ResponseStatus(code = HttpStatus.NOT_FOUND)
public class SomethingNotFoundException extends APIException {
    public SomethingNotFoundException() {
        super(2, "Couldn't find something!");
    }
}

然后，我们应该定义一个捕获这些异常并将其转换为有意义的JSON表示形式。该错误控制器可能如下所示：ErrorController

@RestController
public class APIExceptionHandler extends AbstractErrorController {
    private static final String ERROR_PATH = "/error";
    private final ErrorAttributes errorAttributes;

    @Autowired
    public APIExceptionHandler(ErrorAttributes errorAttributes) {
        super(errorAttributes);
        this.errorAttributes = errorAttributes;
    }

    @RequestMapping(path = ERROR_PATH)
    public ResponseEntity<?> handleError(HttpServletRequest request) {
        HttpStatus status = getStatus(request);

        Map<String, Object> errors = getErrorAttributes(request, false);
        getApiException(request).ifPresent(apiError -> {
            errors.put("message" , apiError.message());
            errors.put("code", apiError.code());
        });
        // If you don't want to expose exception!
        errors.remove("exception");


        return ResponseEntity.status(status).body(errors);
    }

    @Override
    public String getErrorPath() {
        return ERROR_PATH;
    }

    private Optional<APIException> getApiException(HttpServletRequest request) {
        RequestAttributes attributes = new ServletRequestAttributes(request);
        Throwable throwable = errorAttributes.getError(attributes);
        if (throwable instanceof APIException) {
            APIException exception = (APIException) throwable;
            return Optional.of(exception);
        }

        return Optional.empty();
    }
}

因此，如果您抛出一个 ，返回的 JSON 将如下所示：SomethingNotFoundException

{  
   "timestamp":1461621047967,
   "status":404,
   "error":"Not Found",
   "message":"Couldn't find something!",
   "code": 2,
   "path":"/greet"
}

我想如果你想返回一些消息或测试你的错误代码，你可以这样做

@ResponseBody
public ResponseEntity somthing() {
HttpHeaders headers = new HttpHeaders();
headers.add("Content-Type", "application/json; charset=utf-8");
return new ResponseEntity<>(new Gson().toJson("hello this is my message"), headers, HttpStatus.NOT_FOUND);
}