c3p0 - c3p0连接管理问题

Question

我正在使用 Spring 3.0.2、Hibernate 3.5.0 和 c3p0 0.9.1.2，当涉及到检索连接和提交事务时，我遇到了大量错误。这是我对 c3p0 的配置：

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
    <property name="driverClass" value="${jdbc.driverClassName}"/>
    <property name="jdbcUrl" value="${jdbc.url}"/>
    <property name="properties">
        <props>
            <prop key="c3p0.acquireIncrement">5</prop>
            <prop key="c3p0.maxIdleTime">30</prop>
            <prop key="c3p0.idleConnectionTestPeriod">20</prop>
            <prop key="c3p0.maxPoolSize">100</prop>
            <prop key="c3p0.maxStatements">0</prop>
            <prop key="c3p0.minPoolSize">1</prop>
            <prop key="user">${jdbc.username}</prop>
            <prop key="password">${jdbc.password}</prop>
        </props>
    </property>
</bean>

直到最近我经常收到这个错误：

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
Last packet sent to the server was 0 ms ago.

最近我也得到了这些：

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Connection.close() has already been called. Invalid operation in this state.
java.sql.SQLException: Connections could not be acquired from the underlying database!

有什么建议么？

Answer 1

这可能是因为连接超时。检查 idle_test_period 设置或使用具有合理默认值的bonecp http://jolbox.com 。