org.apache.ibatis.exceptions.PersistenceException

今天在mybatis項目中，突然出現下面的錯誤：

org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: org.apache.ibatis.transaction.TransactionException: Error configuring AutoCommit.  Your driver may not support getAutoCommit() or setAutoCommit(). Requested setting: false.  Cause: java.sql.SQLNonTransientConnectionException: Could not send query: Last packet not finished
### The error may exist in cn/com/topsec/mapper/PictureMapper.xml
### The error may involve cn.com.topsec.mapper.PictureMapper.list
### The error occurred while executing a query
### Cause: org.apache.ibatis.transaction.TransactionException: Error configuring AutoCommit.  Your driver may not support getAutoCommit() or setAutoCommit(). Requested setting: false.  Cause: java.sql.SQLNonTransientConnectionException: Could not send query: Last packet not finished

出現這個問題也是偶然，重啓tomcat後，問題就不再存在了。

解決此問題，需要在mybatis(iBatis)的配置文件中加入兩個屬性：poolPingQuery 和 poolPingEnabled。

<?xml version="1.0" encoding="UTF-8" ?>  
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">  
<configuration>  
  
  <typeAliases>  
      ...  
  </typeAliases>  
  
  <environments default="development">  
      <environment id="development">  
          <transactionManager type="JDBC" />  
          <dataSource type="POOLED">  
              <property name="driver" value="${db.driver}" />  
              <property name="url" value="${db.url}" />  
              <property name="username" value="${db.user}" />  
              <property name="password" value="${db.password}" />  
              <property name="poolPingQuery" value="SELECT id FROM user WHERE id = 1" />  
              <property name="poolPingEnabled" value="true" />  
          </dataSource>  
      </environment>  
  </environments>  
  
</configuration>