SpringMVC项目异常处理机制详解

public class BusinessException extends RuntimeException {
    private Integer code;
    public BusinessException(Integer code, String message) {
        super(message);
        this.code = code;
    }
    public Integer getCode() {
        return code;
    }
    public void setCode(Integer code) {
        this.code = code;
    }
}

public class SystemException extends RuntimeException {
    private Integer code;
    public SystemException(Integer code, String message, Throwable cause) {
        super(message, cause);
        this.code = code;
    }
    public Integer getCode() {
        return code;
    }
    public void setCode(Integer code) {
        this.code = code;
    }
}

public class Code {
    public static final Integer SYSTEM_ERR = 50001;
    public static final Integer SYSTEM_TIMEOUT_ERR = 50002;
    public static final Integer SYSTEM_UNKNOWN_ERR = 59999;
    public static final Integer BUSINESS_ERR = 60001;
}

@RestControllerAdvice
public class ProjectExceptionAdvice {
    // 拦截处理业务异常
    @ExceptionHandler(BusinessException.class)
    public Result doBusinessException(BusinessException ex) {
        return new Result(ex.getCode(), null, ex.getMessage());
    }
    // 拦截处理系统异常
    @ExceptionHandler(SystemException.class)
    public Result doSystemException(SystemException ex) {
        // 记录日志，发送消息给运维人员，发送邮件给开发人员
        return new Result(ex.getCode(), null, ex.getMessage());
    }
    //拦截处理其他异常
    @ExceptionHandler(Exception.class)
    public Result doException(Exception ex) {
        // 记录日志，发送消息给运维人员，发送邮件给开发人员
        return new Result(Code.SYSTEM_UNKNOWN_ERR, null, "系统繁忙，请联系管理员。");
    }
}

@Service
public class BookServiceImpl implements BookService {
    @Autowired
    private BookDao bookDao;
    @Override
    public Book getById(Integer id) {
        // id 小于等于零时抛出业务异常
        if (id <= 0) {
            throw new BusinessException(Code.BUSINESS_ERR, "参数不合法，请检查传入参数！");
        }
        // 将可能出现的异常进行包装，装换成自定义异常
        try {
            int x = 1 / 0;  // 加入此行出现异常
            return bookDao.getById(id); // 模拟数据库访问出错
        } catch (Exception e) {
            throw new SystemException(Code.SYSTEM_TIMEOUT_ERR, "数据库访问异常，请稍后重试！", e);
        }
    }
}