SpringBoot实战指南之构建优雅的全局异常处理机制

@PostMapping("/user")
public Result<User> createUser(@RequestBody UserDTO userDTO) {
    try {
        User user = userService.createUser(userDTO);
        return Result.success(user);
    } catch (BizException e) {
        return Result.fail(e.getCode(), e.getMessage());
    } catch (Exception e) {
        log.error("创建用户失败", e);
        return Result.fail(500, "系统内部错误");
    }
}

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Result<T> {
    
    /** 状态码 */
    private Integer code;
    
    /** 提示信息 */
    private String message;
    
    /** 数据载体 */
    private T data;
    
    public static <T> Result<T> success(T data) {
        return new Result<>(200, "success", data);
    }
    
    public static <T> Result<T> success() {
        return new Result<>(200, "success", null);
    }
    
    public static <T> Result<T> fail(Integer code, String message) {
        return new Result<>(code, message, null);
    }
}

@Getter
public class BizException extends RuntimeException {
    
    private final Integer code;
    
    public BizException(Integer code, String message) {
        super(message);
        this.code = code;
    }
    
    // 支持传入枚举类型的错误码
    public BizException(ErrorCode errorCode) {
        super(errorCode.getMessage());
        this.code = errorCode.getCode();
    }
}

// 错误码枚举示例
@Getter
@AllArgsConstructor
public enum ErrorCode {
    
    USER_NOT_FOUND(1001, "用户不存在"),
    USER_ALREADY_EXISTS(1002, "用户已存在"),
    PARAM_ERROR(1003, "参数错误");
    
    private final Integer code;
    private final String message;
}

@Slf4j
@RestControllerAdvice
public class GlobalExceptionHandler {

    /**
     * 处理自定义业务异常
     */
    @ExceptionHandler(BizException.class)
    public Result<?> handleBizException(BizException e) {
        log.warn("业务异常: code={}, msg={}", e.getCode(), e.getMessage());
        return Result.fail(e.getCode(), e.getMessage());
    }

    /**
     * 处理参数校验异常 (Hibernate Validator)
     */
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public Result<?> handleValidationException(MethodArgumentNotValidException e) {
        String message = e.getBindingResult().getFieldErrors().stream()
                .map(DefaultMessageSourceResolvable::getDefaultMessage)
                .collect(Collectors.joining(", "));
        log.warn("参数校验异常: {}", message);
        return Result.fail(ErrorCode.PARAM_ERROR.getCode(), message);
    }

    /**
     * 处理非法参数异常
     */
    @ExceptionHandler(IllegalArgumentException.class)
    public Result<?> handleIllegalArgumentException(IllegalArgumentException e) {
        log.warn("非法参数异常: {}", e.getMessage());
        return Result.fail(400, e.getMessage());
    }

    /**
     * 兜底处理：处理所有未被捕获的异常
     */
    @ExceptionHandler(Exception.class)
    public Result<?> handleException(Exception e) {
        log.error("系统未知异常: ", e);
        return Result.fail(500, "系统繁忙，请稍后再试");
    }
}

@PostMapping("/user")
public Result<User> createUser(@Valid @RequestBody UserDTO userDTO) {
    // 业务逻辑，无需 try-catch
    User user = userService.createUser(userDTO);
    return Result.success(user);
}