再谈java自定义异常（Exception）

再谈java自定义异常（Exception）

java学习书籍上，必然对java异常进行很详细的介绍，这里笔者不必再累述；如今分布式系统设计已经深入普及到我们工作挡住，随着系统的服务逐渐模块化，业务的复杂度日益增加，那么对异常的处理即打印异常到客户端，就显得十分重要了，项目研发过程中，兄弟们的资质参差不齐，所以，对异常的封装也是必不可少的工作。

这里，笔者谈谈自己的异常设计感受，当然如果有更好的设计思想与实践，也可与笔者一同分享。

首先，我们应该分两大异常类：

    1、系统异常

    2、业务异常

毋庸置疑，系统异常也就是因程序不健壮或者因为数据影响引发的异常，是本服务抛出的，与外界服务、系统没有关系

一、创建系统异常类：SysException

/**
 * @ClassName SysException
 * @Description 系统异常
 * @author jrlisheng5
 * @Date 2016年6月14日 下午2:41:29
 * @version 1.0.0
 */
public class SysException extends Exception {

    private static final long serialVersionUID = -4742832112872227456L;
    /**系统错误码*/
    private String code;
    /**错误描述*/
    private String msg;
    
    public SysException() {
        super();
    }
    public SysException(Throwable t) {
        super(t);
    }
    public SysException(String code, String msg) {
        super(code + '|' + msg);
        this.code = code;
        this.msg = msg;
    }
    public String getCode() {
        return code;
    }
    public void setCode(String code) {
        this.code = code;
    }
    public String getMsg() {
        return msg;
    }
    public void setMsg(String msg) {
        this.msg = msg;
    }
    @Override
    public String toString() {
        return ReflectionToStringBuilder.toString(this);
    }
}

业务异常，又可能是服务A、服务B，外界系统A、外界系统B，抛给客户端某个请求的，所有区别于系统的设计是，多了外界异常 描述

一、创建业务异常类：ServiceException

/**
 * @ClassName ServiceException
 * @Description 业务异常
 * @author jrlisheng5
 * @Date 2016年6月14日 下午2:47:16
 * @version 1.0.0
 */
public class ServiceException extends RuntimeException {
	private static final long serialVersionUID = -4742832112872227456L;
	/**系统错误码*/
	private String code;
	/**错误描述*/
	private String msg;
	/**外部错误码*/
	private String logMsg;
	
	public ServiceException() {
		super();
	}
	public ServiceException(Throwable t) {
		super(t);
	}
	
	public ServiceException(String code, String msg) {
		super(code + '|' + msg);
		this.code = code;
		this.msg = msg;
	}
	public ServiceException(String code, String msg, String logMsg) {
		super(code + '|' + msg +  '|' + logMsg);
		this.code = code;
		this.msg = msg;
		this.logMsg = logMsg;
	}
	public String getCode() {
		return code;
	}
	public void setCode(String code) {
		this.code = code;
	}
	public String getMsg() {
		return msg;
	}
	public void setMsg(String msg) {
		this.msg = msg;
	}
	public String getLogMsg() {
		return logMsg;
	}
	public void setLogMsg(String logMsg) {
		this.logMsg = logMsg;
	}
	
	@Override
    public String toString() {
        return ReflectionToStringBuilder.toString(this);
    }
}

短信验证码验证失败异常，即业务异常

三、定义短信验证异常类

/**
 * @ClassName SmsValidatorException
 * @Description 短信验证异常
 * @author jrlisheng5
 * @Date 2016年6月14日 下午3:13:13
 * @version 1.0.0
 */
public class SmsValidatorException extends ServiceException {

	private static final long serialVersionUID = -647562559025214578L;

	private String smsVerfifyCode;

	public SmsValidatorException() {
		super();
	}

	public SmsValidatorException(String code, String msg,String smsVerfifyCode) {
		super(code, msg);
		this.smsVerfifyCode = smsVerfifyCode;
	}

	public SmsValidatorException(String code, String msg, String logMsg,String smsVerfifyCode) {
		super(code, msg, logMsg);
		this.smsVerfifyCode = smsVerfifyCode;
	}

	public String getSmsVerfifyCode() {
		return smsVerfifyCode;
	}

	public void setSmsVerfifyCode(String smsVerfifyCode) {
		this.smsVerfifyCode = smsVerfifyCode;
	}

	@Override
    public String toString() {
        return ReflectionToStringBuilder.toString(this);
    }

有异常抛出的时候，将异常系统反馈给客户端

四、客户端异常反馈类：ClientResponse<T>

/**
 * @Package com.jd.jr.fp.front.domain.response
 * @ClassName AppResponse
 * @Description. 客户端消息反馈对象
 * @author lisheng
 * @Date. 2016年6月14日 下午2:51:49
 * @version 1.0.0
 * @param <T>
 */
public class ClientResponse<T> {

    private static final int SUCCESS_CODE = 0;
    /** 异常编号 */
    private static final int FIAL_CODE = -1;
    /** 未登录 */
    private static final int NOT_LOGIN_CODE = -2;
    /** 未授权 */
    private static final int NOT_REALNAME_CODE = -3;

    private int resultCode;

    private Result resultMsg;

    private T resultData;

    public ClientResponse() {
    }

    public ClientResponse(int resultCode) {
        this.resultCode = resultCode;
    }

    public ClientResponse(int resultCode, String code, String msg) {
        this.resultCode = resultCode;
        this.resultMsg = new Result(code, msg);
    }

    public ClientResponse(int resultCode, T resultData) {
        this.resultCode = resultCode;
        this.resultData = resultData;
    }

    public int getResultCode() {
        return resultCode;
    }

    public Result getResultMsg() {
        return resultMsg;
    }

    public T getResultData() {
        return resultData;
    }

    @Override
    public String toString() {
        return ReflectionToStringBuilder.toString(this);
    }

    public static <T> ClientResponse<T> respSuccess(T respDate) {
        return new ClientResponse<T>(SUCCESS_CODE, respDate);
    }

    public static <T> ClientResponse<T> respFail() {
        return new ClientResponse<T>(FIAL_CODE, "-1", "系统运维中，请稍后再试。");
    }

    public static <T> ClientResponse<T> respFail(String code, String msg) {
        return new ClientResponse<T>(FIAL_CODE, code, msg);
    }

    public static <T> ClientResponse<T> respLoginFail() {
        return new ClientResponse<T>(NOT_LOGIN_CODE);
    }

    public static <T> ClientResponse<T> respRealNameFail(T respDate) {
        return new ClientResponse<T>(NOT_REALNAME_CODE, respDate);
    }

    /**
     * 错误码对象
     * 
     * @author lisheng
     * @date 2016-5-18 09:29:26
     */
    public class Result {

        private String code;

        private String msg;

        public Result() {

        }

        public Result(String code, String msg) {
            this.code = code;
            this.msg = msg;
        }

        public String getCode() {
            return code;
        }

        public void setCode(String code) {
            this.code = code;
        }

        public String getMsg() {
            return msg;
        }

        public void setMsg(String msg) {
            this.msg = msg;
        }

        @Override
        public String toString() {
            return ReflectionToStringBuilder.toString(this);
        }
    }
}

将返回对象反馈到客户端

五、定义测试案例：

        @RequestMapping("init")
	@ResponseBody
	public ClientResponse<InitRespVo> init(@RequestBody InitReqVo reqVo, HttpServletRequest request) {
		try {
			logger.infof("init req：", reqVo.toString());
			InitRespVo result = service.init(reqVo);
			logger.infof("init resp：",result.toString());
			return ClientResponse.respSuccess(result);
		} catch (AppException e) {
			logger.error("/init fail：",e.getLogDesc());
			return ClientResponse.respFail(String.valueOf(e.getCode()), e.getLogDesc());
		} catch (Exception e) {
			logger.error("/FixedredeemPayCtrl.init error：",e);
			return ClientResponse.respFail();
		}
	}