tomcat jndi 连接 mysql 报 BEGIN NESTED EXCEPTION 错误的解决办法

我在 tomcat conf 目录下配置了一个jndi

<Resource  
		name="jdbc/mydb"   
		scope="Shareable"   
		type="javax.sql.DataSource"  
		factory="org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory"  
		url="jdbc:mysql://localhost:3306/mydb"  
		driverClassName ="com.mysql.jdbc.Driver"  
		username="aaa"  
		password="123456"
	/>

刚开始使用没问题，一段时间之后出现这个错误

com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: 

** BEGIN NESTED EXCEPTION ** 

java.io.EOFException

STACKTRACE:

java.io.EOFException
 at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1956)
 at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2368)
 at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2867)
 at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1616)
 at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1708)
 at com.mysql.jdbc.Connection.execSQL(Connection.java:3255)
 at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1293)
 at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1428)
 at org.apache.tomcat.dbcp.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:93)
 at com.blasetti.ordiniweb.dao.OrdiniDAO.caricaOrdine(OrdiniDAO.java:263)
...
** END NESTED EXCEPTION **



Last packet sent to the server was 0 ms ago.
 com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2579)
 com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2867)
 com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1616)
 com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1708)
 com.mysql.jdbc.Connection.execSQL(Connection.java:3255)
 com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1293)
 com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1428)
 org.apache.tomcat.dbcp.dbcp.DelegatingPreparedStatement.executeQuery(DelegatingPreparedStatement.java:93)
 com.blasetti.ordiniweb.dao.OrdiniDAO.caricaOrdine(OrdiniDAO.java:263)
...

这是因为服务端一段时间之后会假定客户端已经断开连接了，所以主动断开，而客户端不知道，所以再使用这个连接池的时候就会报这个错。解决办法是配置客户端连接池的定期检查

<Resource  
		name="jdbc/mydb"   
		scope="Shareable"   
		type="javax.sql.DataSource"  
		factory="org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory"  
		url="jdbc:mysql://localhost:3306/mydb?autoReconnect=true&useUnicode=true&characterEncoding=utf8"  
		driverClassName ="com.mysql.jdbc.Driver"  
		username="abc"  
		password="123456"
		validationQuery="Select 1"
		maxActive="100" 
		maxIdle="30" 
		maxWait="10000"
	/>

解释下

• 增加?autoReconnect=true&useUnicode=true&characterEncoding=utf8
• 增加validationQuery="Select 1"