org.hibernate.TransactionException: JDBC begin transaction failed:

启动tomcat时报了下面的错：

=2013-08-06 10:52:37,849 ERROR [Timer-5] timer.SystemMonitoringTimer (SystemMonitoringTimer.java:331)     -  oops, got an exception:
org.springframework.transaction.CannotCreateTransactionException: Could not open Hibernate Session for transaction; nested exception is org.hibernate.TransactionException: JDBC begin transaction failed: 
	at org.springframework.orm.hibernate4.HibernateTransactionManager.doBegin(HibernateTransactionManager.java:440)
	at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:371)
	at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:335)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:105)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:90)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
	at $Proxy22.getAllThresholdInfo(Unknown Source)
	at com.xxxxxxx.oam.systemmonitoring.timer.SystemMonitoringTimer.run(SystemMonitoringTimer.java:108)
	at java.util.TimerThread.mainLoop(Timer.java:512)
	at java.util.TimerThread.run(Timer.java:462)
Caused by: org.hibernate.TransactionException: JDBC begin transaction failed: 
	at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:76)
	at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:160)
	at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1309)
	at org.springframework.orm.hibernate4.HibernateTransactionManager.doBegin(HibernateTransactionManager.java:399)
	... 11 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet successfully received from the server was 9,961 milliseconds ago.  The last packet sent successfully to the server was 0 milliseconds ago.
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
	at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
	at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3052)
	at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2938)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3481)
	at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1959)
	at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2109)
	at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2642)
	at com.mysql.jdbc.ConnectionImpl.setAutoCommit(ConnectionImpl.java:5034)
	at com.mchange.v2.c3p0.impl.NewProxyConnection.setAutoCommit(NewProxyConnection.java:881)
	at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:72)
	... 14 more
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
	at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2497)
	at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2949)
	... 22 more

发现报了该错后并不影响系统的功能，事务数据库操作什么的都是OK的，这个错误比较奇怪：如果事务无法开启，那后面的数据库操作应该都无法进行才对呀，可是事实上又不是这样

后来发现是每次把服务器加电开启时才会报这个错，由于我的mysql tomcat等服务都是在开机时自启动的或者是被watchdog自动叫起来的，于是就在想是不是在开机时mysql服务没有完全启动引起的，后来经过测试确定是该原因


于是在tomcat的startup.sh脚本中加上以下语句：

#判断进程mysqld 是否存在，如果不存在就启动它
echo "check The mysqld whether running"
PIDS=`ps -ef |grep mysqld |grep -v grep | awk '{print $2}'`
while [ "$PIDS"x == ""x ]; do
    echo "The mysqld is not running"
    service mysqld start
    sleep 5
    PIDS=`ps -ef |grep mysqld |grep -v grep | awk '{print $2}'`
done
echo "The mysqld is running"

这样就避免了该错误的发生

评论

1 楼 无双Rama 2013-09-12  

alter table 表名 modify column 字段名 类型;
例如
数据库中user表 name字段是varchar(30)
可以用
alter table user modify column name varchar(50) ;
alter table LocCondTask modify column Reserved1 varchar(100) ;