异常补偿解决方案

问题 

我们在捕获到异常并对异常进行处理时可能会遇到如下一些问题： 

1. 不确定应如何处理这些异常
2. 需要记录异常日志时没有记录，或者异常在不同的地方重复记录，使得排错调试不方便
3. 处理日志时，需要在每一个try-catch块包含一些处理代码，有时候异常处理的代码比正常执行代码还多，污染正常执行代码。
4. 同样类型异常有不同的处理方式，使最终的处理变得复杂。
5. 接口抛出异常，破坏封装，打破了接口与实现之间的清晰界限。
6. 异常处理代码散落在，修改起来时非常麻烦。无法对某些异常进行统一处理和修改。

有必要使用一个统一的异常处理机制 来进行某些异常处理的统一决策。比如对异常进行统一的日志记录，对散落在各处的某类异常进行统一处理等。

目标

1. 保障数据前后一致性，包括与外系统数据的一致性

2. 将业务代码与补偿代码解耦

3. 补偿框架易用性

解决办法 

使用Spring AOP对serivce层抛出的异常进行拦截，记录所有未处理的异常日志，并将所有未处理异常转换成统一自定义的系统异常，以便前端能够处理。下面的代码举例说明了如何使用Spring AOP将异常处理从正常的逻辑中分离出来，使得异常处理逻辑和正常的业务逻辑做到完全解耦。不同项目对于异常处理的要求不同，在具体项目中需要对异常处理代码根据项目需要进行修改，加以完善。

模块分解

异常捕获

1. AOP配置

   .*.*.impl.*

   
   

2. 异常处理类

   package com.za.exceptionhandler.demo.exception.aop; import java.lang.reflect.Method; import java.util.logging.Level; import java.util.logging.Logger; import org.springframework.aop.ThrowsAdvice; import com.za.exceptionhandler.demo.util.SpringContextUtil; import com.za.exceptionhandler.router.support.Compensation; import com.za.exceptionhandler.router.support.CompensationService; public class ExceptionHandler implements ThrowsAdvice { private Logger logger = Logger.getLogger(this.getClass().getName()); public void afterThrowing(Method method, Object[] args, Object target, Exception ex) throws Throwable { logger.log(Level.INFO, args[0] + " 执行 " + method.getName() + "时有异常抛出..." + ex); method=target.getClass().getMethod(method.getName(), method.getParameterTypes()); if (method.isAnnotationPresent(Compensation.class)) { Compensation compensation = method.getAnnotation(Compensation.class); CompensationService compensationService = (CompensationService) SpringContextUtil.getBean(compensation.beanName()); compensationService.process(compensation.beanName(), method, args, target, ex); } } }

   
   

补偿路由

1. 补偿配置

   package com.za.exceptionhandler.demo.service.impl; import java.util.concurrent.TimeoutException; import org.springframework.stereotype.Service; import com.za.exceptionhandler.demo.service.UserService; import com.za.exceptionhandler.router.support.Compensation; @Service public class UserServiceImpl implements UserService { @Compensation(beanName = "userAddCompensationService") public void addUser(String name) throws Exception { System.out.println("add user"); throw new Exception("Exception"); } @Compensation(beanName = "userUpdateCompensationService") public void updateUser(String name, String sex) throws Exception { System.out.println("update user"); throw new TimeoutException("超时。。。"); } }

   
   

2. 异常解析（暂未实现）
   暂时没有复杂场景，如需对异常进行判断后，才可路由，可以先进行异常解析，将Exception中的堆栈进行解析，得到路由的key值

3. 补偿路由

   method=target.getClass().getMethod(method.getName(), method.getParameterTypes()); if (method.isAnnotationPresent(Compensation.class)) { Compensation compensation = method.getAnnotation(Compensation.class); CompensationService compensationService = (CompensationService) SpringContextUtil.getBean(compensation.beanName()); compensationService.process(compensation.beanName(), method, args, target, ex); }

   
   

补偿执行

1. 立即执行

   package com.za.exceptionhandler.router.support; import com.za.exceptionhandler.router.support.CompensationService; import org.springframework.stereotype.Service; @Service("userAddCompensationService") public class UserAddCompensationServiceImpl implements CompensationService { @Override public void process(String key, Method method, Object[] args, Object target, Exception e) { System.out.println("新增补偿"); } }

   
   

2. 定时执行（暂未实现）
   定时执行是指不立即进行补偿，只启动定时任务，在预定的时间进行补偿，这样可以避开网络拥堵，系统并发高的情况，可以设定补偿时间、补偿次数等

异常转人工

1. 转人工处理
   1. 记录数据库
      

      数据表结构

      Field	Type	Null	Default	Comment
      id	bigint(20)	NO	(null)	主键
      Log_Type	CHAR(1)	NO	(null)	日志类型（0：一般代码异常；1:补偿代码异常）
      exception_name	varchar(256)	YES	(null)	异常名称
      exception_position	varchar(256)	YES	(null)	异常位置
      exception_detail	text	YES	(null)	异常详细信息
      state	char(1)	NO	(null)	处理状态（0：待处理，1：处理中，2：已处理）
      routing_key	varchar(128)	YES	(null)	路由key
      compensation_class	varchar(128)	YES	(null)	补偿处理类
      compensation_params	text	YES	(null)	补偿参数
      compensation_detail	text	YES	(null)	补偿详细信息
      creator	varchar(128)	YES	(null)	创建用户
      modifier	varchar(128)	YES	(null)	更新用户
      create_time	datetime	YES	(null)	创建时间
      update_time	datetime	YES	(null)	更新时间
      is_delete	char(1)	YES	(null)	是否删除
      Ext1	varchar(256)	YES	(null)	预留字段1
      Ext2	varchar(1024)	YES	(null)	预留字段2

      
      

2. 转人工告警

   1. 发送mail通知

      package com.za.exceptionhandler.demo.util; import java.io.PrintWriter; import java.io.StringWriter; import java.lang.reflect.Method; import java.util.Map; import java.util.Properties; import javax.activation.DataHandler; import javax.mail.BodyPart; import javax.mail.Message; import javax.mail.Multipart; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeBodyPart; import javax.mail.internet.MimeMessage; import javax.mail.internet.MimeMultipart; import javax.mail.internet.MimeUtility; import javax.mail.util.ByteArrayDataSource; import lombok.extern.slf4j.Slf4j; import org.springframework.mail.SimpleMailMessage; import org.springframework.mail.javamail.JavaMailSenderImpl; import org.springframework.util.StringUtils; import com.alibaba.fastjson.JSON; @Slf4j public class MailUtil { private static JavaMailSenderImpl senderImpl = new JavaMailSenderImpl(); static{ // 设定mail server senderImpl.setHost("smtp.163.com"); senderImpl.setPort(25); senderImpl.setUsername("[email protected]"); // 根据自己的情况,设置username senderImpl.setPassword("xxxxxx"); // 根据自己的情况, 设置password senderImpl.setDefaultEncoding("utf-8"); Properties prop = new Properties(); prop.put("mail.smtp.auth", "true"); // 将这个参数设为true，让服务器进行认证,认证用户名和密码是否正确 prop.put("mail.smtp.timeout", "60000"); senderImpl.setJavaMailProperties(prop); } public static boolean send(String[] to, String from, String subject, String text) { try{ log.info("sent mail subject:" + subject + " from:" + from +" to:" + JSON.toJSONString(to)); // 建立邮件消息 SimpleMailMessage mailMessage = new SimpleMailMessage(); mailMessage.setTo(to); mailMessage.setFrom(from); mailMessage.setSubject(subject); mailMessage.setText(text); // 发送邮件 senderImpl.send(mailMessage); return true; }catch(Exception e){ log.error("sent mail subject:" + subject + " error",e); } return false; } public static boolean send(String[] to, String from, String subject, String text, Map param) { for (String key : param.keySet()){ text.replace("$$"+key+"#$", param.get(key)); } return send(to, from, subject, text); } public static boolean sendHtmlMail(String[] to, String from, String[] cc, String subject, String htmlContent,String filename, String ... attachContents){ try { MimeMessage mm= new MimeMessage(senderImpl.getSession()); Multipart mp = new MimeMultipart(); mm.setSubject(subject); BodyPart bp = new MimeBodyPart(); bp.setContent("" + htmlContent.replace("\n"," "), "text/html;charset=GBK"); mp.addBodyPart(bp); mm.setFrom(new InternetAddress(from)); mm.setRecipients(Message.RecipientType.TO, InternetAddress.parse(StringUtils.arrayToDelimitedString(to, ","))); if(cc!=null){ mm.setRecipients(Message.RecipientType.CC, InternetAddress.parse(StringUtils.arrayToDelimitedString(cc, ","))); } if(attachContents!=null && attachContents.length>0){ for (String attachContent : attachContents) { MimeBodyPart pt = new MimeBodyPart(); ByteArrayDataSource fields = new ByteArrayDataSource(attachContent, "text/plain"); pt.setDataHandler(new DataHandler(fields)); pt.setFileName(MimeUtility.encodeText(filename)); mp.addBodyPart(pt); } } mm.setContent(mp); mm.saveChanges(); senderImpl.send(mm); return true; } catch (Exception e) { log.error("sent mail subject:" + subject + " error",e); } return false; } public boolean alert(String id, String[] to, String key, Method method, Object[] args, Object target, Exception e){ String subject = "[异常警告][" + id + "]" + target.getClass().getSimpleName() + "." + method.getName() + "异常，请及时处理"; StringBuffer textBuf = new StringBuffer("异常信息：\n"); if(id != null) textBuf.append("id:" + id + "\n"); if(key != null) textBuf.append("routeKey:" + key + "\n"); if(target != null) textBuf.append("class:" + target.getClass().getName() + "\n"); if(method != null) textBuf.append("method:" + method.getName() + "\n"); if(args != null) textBuf.append("params:" + JSON.toJSONString(args) + "\n"); textBuf.append("exception:"); if(e != null){ StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw); e.printStackTrace(pw); textBuf.append(sw.toString() + "\n"); pw.close(); } else { textBuf.append("exception is null\n"); } return MailUtil.send(to, "[email protected]", subject, textBuf.toString()); } public boolean alert(String id, String[] to, String key, Method method, Object[] args, Object target, Exception e, Object handler, Exception he){ String subject = "[异常警告][" + id + "]" + target.getClass().getSimpleName() + "." + method.getName() + "异常，请及时处理"; StringBuffer textBuf = new StringBuffer("异常信息：\n"); if(id != null) textBuf.append("id:" + id + "\n"); if(key != null) textBuf.append("routeKey:" + key + "\n"); if(target != null) textBuf.append("class:" + target.getClass().getName() + "\n"); if(method != null) textBuf.append("method:" + method.getName() + "\n"); if(args != null) textBuf.append("params:" + JSON.toJSONString(args) + "\n"); textBuf.append("exception:"); if(e != null){ StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw); e.printStackTrace(pw); textBuf.append(sw.toString() + "\n"); pw.close(); } else { textBuf.append("exception is null\n"); } textBuf.append("-----------------------------------------------------------\n"); if(handler != null) textBuf.append("class:" + handler.getClass().getName() + "\n"); textBuf.append("handler exception:"); if(he != null){ StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw); he.printStackTrace(pw); textBuf.append(sw.toString() + "\n"); pw.close(); } else { textBuf.append("handler exception is null\n"); } return MailUtil.send(to, "[email protected]", subject, textBuf.toString()); } public static void main(String[] args) { String[] to = {"[email protected]","[email protected]"}; MailUtil.send(to, "[email protected]", "异常处理警告", "异常处理警告：程序执行异常补偿出错，请赶紧处理"); } }

      
      

补偿查询（二期）

可进行补偿情况的查询，或是需要人工处理的记录查询

补偿动态配置（二期）

补偿路由，补偿方式可动态配置