使用c3p0，偶尔会报异常：

ERROR Thread-4 com.feedsky.dao.AbstractMutiDbDAO - 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:1913)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2304)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2803)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1573)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1665)
        at com.mysql.jdbc.Connection.execSQL(Connection.java:3170)
        at com.mysql.jdbc.Connection.execSQL(Connection.java:3099)
        at com.mysql.jdbc.Statement.executeQuery(Statement.java:1169)
        at com.mchange.v2.c3p0.impl.NewProxyStatement.executeQuery(NewProxyStatement.java:35)
        at com.feedsky.dao.AbstractMutiDbDAO.findBySQL(AbstractMutiDbDAO.java:34)
        at com.feedsky.dao.impl.SrcItemDAOImpl.findBySQL(SrcItemDAOImpl.java:326)
        at com.feedsky.dao.impl.SrcItemDAOImpl.loadByItemUuid(SrcItemDAOImpl.java:255)
        at com.feedsky.service.impl.SrcItemServiceImpl.loadByItemUuid(SrcItemServiceImpl.java:37)
        at com.feedsky.controller.SrcFeedController.saveSrcFeed(SrcFeedController.java:97)
        at com.feedsky.work.SrcStoreThread.saveSrcFeed(SrcStoreThread.java:174)
        at com.feedsky.work.SrcStoreThread.run(SrcStoreThread.java:53)
        at EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Worker.run(PooledExecutor.java:748)
        at java.lang.Thread.run(Thread.java:619)


** END NESTED EXCEPTION **



Last packet sent to the server was 176 ms ago.
2008-02-18 10:52:53 ERROR Thread-4 com.feedsky.work.SrcStoreThread - java.lang.NullPointerException
2008-02-18 10:52:53 INFO Thread-2 com.feedsky.dao.impl.SrcItemDAOImpl - 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:1913)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2304)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2803)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1573)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1665)
        at com.mysql.jdbc.Connection.execSQL(Connection.java:3170)
        at com.mysql.jdbc.Statement.executeUpdate(Statement.java:1316)
        at com.mysql.jdbc.Statement.executeUpdate(Statement.java:1235)
        at com.mchange.v2.c3p0.impl.NewProxyStatement.executeUpdate(NewProxyStatement.java:64)
        at com.feedsky.dao.impl.SrcItemDAOImpl.insert(SrcItemDAOImpl.java:178)
        at com.feedsky.service.impl.SrcItemServiceImpl.save(SrcItemServiceImpl.java:29)
        at com.feedsky.controller.SrcFeedController.saveSrcFeed(SrcFeedController.java:111)
        at com.feedsky.work.SrcStoreThread.saveSrcFeed(SrcStoreThread.java:174)
        at com.feedsky.work.SrcStoreThread.run(SrcStoreThread.java:53)
        at EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Worker.run(PooledExecutor.java:748)
        at java.lang.Thread.run(Thread.java:619)

** END NESTED EXCEPTION **

?在google和javaeye搜索了下，做了如下处理，但是还是会报错。

public synchronized static DataSource createDataSource(String driver,String url,String username,String password) throws SQLException, ClassNotFoundException {
		
		Class.forName(driver);
		
		DataSource ds_unpooled = DataSources.unpooledDataSource(url,username,password); 
		
		Map overrides = new HashMap(); 
		//当连接池中的连接耗尽的时候c3p0一次同时获取的连接数。Default: 3 
		overrides.put("acquireIncrement", 5);
		overrides.put("minPoolSize", 5);
		overrides.put("maxPoolSize", 10);
		//overrides.put("initialPoolSize",cfg.getMaxPoolSize());
		overrides.put