毕设系统问题集

1.The remote endpoint was in state [TEXT_FULL_MRITIN6] which is an invalid state for calledmethod 

产生原因:同时有多个线程调用了this.session.getBasicRemote( ) .sendText(msg)

解决：synchronized(this.session)

 

2.重复推送，推测跟新闻列表的时间顺序不对有关

等待线上日志反馈......

日志反馈：时间顺序正确，推测是线程同步问题，加锁的地方有问题，修改静态变量发生了线程不安全。

解决：synchronized 具体service方法的 try catch块问题解决

 

3.SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6b3a9668] was not registered for synchronization because synchronization is not active

解决：用@Transactional给定时方法开启事务

 

4. 负载均衡的其他容器请求不到静态文件

解决：轮询策略改为ip_hash

 

5. 线上日志显示反复插入重复数据

2022-03-31 10:58:42.329  INFO 1 --- [My-Async-ThreadPool-2-10] c.m.I.S.MultithreadScheduleTask          : 更新数据库的国内外新闻信息失败！
### Error updating database.  Cause: java.sql.SQLIntegrityConstraintViolationException: Duplicate entry '江苏新增本土确诊病例5例和本土无症状感染者41' for key 'epidemic_news.PRIMARY'
### The error may exist in com/major/IEMSystem/mapper/EpidemicNewsMapper.java (best guess)
### The error may involve com.major.IEMSystem.mapper.EpidemicNewsMapper.insert-Inline
### The error occurred while setting parameters
### SQL: INSERT INTO epidemic_news  ( event_description, event_time, event_url,   site_name )  VALUES  ( ?, ?, ?,   ? )
### Cause: java.sql.SQLIntegrityConstraintViolationException: Duplicate entry '江苏新增本土确诊病例5例和本土无症状感染者41' for key 'epidemic_news.PRIMARY'
; Duplicate entry '江苏新增本土确诊病例5例和本土无症状感染者41' for key 'epidemic_news.PRIMARY'; nested exception is java.sql.SQLIntegrityConstraintViolationException: Duplicate entry '江苏新增本土确诊病例5例
和本土无症状感染者41' for key 'epidemic_news.PRIMARY'
2022-03-31 10:59:42.393  INFO 1 --- [My-Async-ThreadPool-2-11] c.m.I.S.MultithreadScheduleTask          : 更新数据库的国内外新闻信息失败！
### Error updating database.  Cause: java.sql.SQLIntegrityConstraintViolationException: Duplicate entry '江苏新增本土确诊病例5例和本土无症状感染者41' for key 'epidemic_news.PRIMARY'
### The error may exist in com/major/IEMSystem/mapper/EpidemicNewsMapper.java (best guess)
### The error may involve com.major.IEMSystem.mapper.EpidemicNewsMapper.insert-Inline
### The error occurred while setting parameters
### SQL: INSERT INTO epidemic_news  ( event_description, event_time, event_url,   site_name )  VALUES  ( ?, ?, ?,   ? )

排查问题：

　　首先排除后端逻辑错误------------因为只有这一条数据出错

　　主键(event_description)值已存在，又因为插入逻辑是根据event_time的值确定的，遂去数据库找到这条数据，发现时间比待插入的这条数据的event_time小

结论：百度的接口有问题，同一条新闻的时间，有可能发生更改（属实离谱！！！）

解决：把数据库的主键改为复合主键（event_description,event_time)

6.MySQL死锁

### Error updating database.  Cause: com.mysql.cj.jdbc.exceptions.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction
### The error may exist in com/major/IEMSystem/mapper/ChinaHistoryDataMapper.java (best guess)
### The error may involve com.major.IEMSystem.mapper.ChinaHistoryDataMapper.update-Inline
### The error occurred while setting parameters
### SQL: UPDATE china_history_data  SET date=?, today_confirm=?, today_dead=?, today_heal=?, today_input=?, today_suspect=?, today_exist_confirm=?, total_dead=?, total_heal=?, total_input=?, total_confirm=?      WHERE date = ?
### Cause: com.mysql.cj.jdbc.exceptions.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction

问题来源：两个开启事务的定时任务都执行了同一个表的update方法，导致其中一个事务加锁失败

解决：合并两个定时任务

 

7.adminUpdate失败

问题原因：定时任务的修改的数据跟主动更新的数据是同一行，主动更新呗被定时任务的事务更新覆盖

定时任务事务开启---定时任务读---主动更新读写---定时任务写---定时任务提交

解决：更改数据库表的结构，做水平拆分，使更新的数据不在同一行