Spring boot 404错误自定义错误响应ReST

使用Spring Boot开发RESTful API时，我们经常会遇到404错误，即请求的资源未找到。默认情况下，Spring Boot会返回一个简单的错误响应，但有时我们希望能够自定义404错误的响应内容。在本文中，我们将探讨如何 来介绍如何自定义404错误响应，并提供一个示例代码。

java
@ControllerAdvice
public class CustomExceptionHandler {
    @ExceptionHandler(NoHandlerFoundException.class)
    @ResponseStatus(HttpStatus.NOT_FOUND)
    @ResponseBody
    public ErrorResponse handleNoHandlerFoundException(HttpServletRequest request, NoHandlerFoundException ex) {
        ErrorResponse errorResponse = new ErrorResponse();
        errorResponse.setErrorCode(HttpStatus.NOT_FOUND.value());
        errorResponse.setMessage("资源未找到");
        errorResponse.setPath(request.getRequestURI());
        return errorResponse;
    }
}

java
public class ErrorResponse {
    private int errorCode;
    private String message;
    private String path;
    // getters and setters
}

java
@RestController
public class UserController {
    @GetMapping("/users/{id}")
    public ResponseEntity getUser(@PathVariable Long id) {
        // 根据用户id查询用户信息
        User user = userRepository.findById(id).orElse(null);
        if (user == null) {
            throw new NoHandlerFoundException();
        }
        return ResponseEntity.ok(user);
    }
}