Java报错状态码快速定位与解决方法

// 一个简单的Spring Boot控制器
@RestController
public class MyController {
    @GetMapping("/test")
    public String test() {
        return "Hello World";
    }
}

@GetMapping("/success")
public ResponseEntity<String> success() {
    return ResponseEntity.ok("请求成功");
}

@GetMapping("/old")
public String old() {
    return "redirect:/new";
}

@PostMapping("/user")
public ResponseEntity createUser(@Valid @RequestBody User user) {
    // 如果user对象校验失败会自动返回400
    return ResponseEntity.ok(userService.create(user));
}

@GetMapping("/notfound")
public ResponseEntity notFound() {
    return ResponseEntity.notFound().build();
}

@GetMapping("/error")
public String error() {
    // 故意抛出异常
    throw new RuntimeException("出错了！");
}

@GetMapping("/users/{id}")
public ResponseEntity<User> getUser(@PathVariable Long id) {
    User user = userService.findById(id);
    if (user == null) {
        return ResponseEntity.notFound().build(); // 返回404
    }
    return ResponseEntity.ok(user); // 返回200
}

@GetMapping("/custom")
public ResponseEntity<ApiResponse> custom() {
    ApiResponse response = new ApiResponse();
    response.setCode(1001);
    response.setMessage("自定义错误");
    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(response);
}