将正文添加到404未找到异常

Question

在用JHipster生成的REST API中，我想抛出一些404异常。通常用

return new ResponseEntity<>(HttpStatus.NOT_FOUND);

这实际上会导致对xhr请求的404响应。问题是，在前面，JHipster用

angular.fromJson(result)

当404是实际响应时，这样的结果为空，这使得解析失败。

{
    "timestamp": "2016-04-25T18:33:19.947+0000",
    "status": 404,
    "error": "Not Found",
    "message": "No message available",
    "path": "/api/user/myuser/contact"
}

我试过这个：Spring-MVC控制器中的触发器404？但我无法设置响应的参数。

Answer 1

第一个选项是定义错误对象，并将它们返回为404 Not found正文。如下所示：

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

您可以抛出一个异常而不是返回典型的responseEntity，该异常将解析为404 Not found。假设您有一个NotFoundException类似：

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

那么如果在控制器中抛出此异常,您将看到如下内容：

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

例如，您可以引入一个异常，例如APIException，它是控制器抛出的所有其他异常的超类。此类定义了一个代码/消息对,如下所示：

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;
    }
}

每个子类都可以根据其异常的性质为这对子类提供一些合理的值。例如，我们可以有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找不到的：

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

@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();
    }
}

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