tomcat数据库连接池问题

在mysql的设置中有两个选项，主动断开空闲连接的等待时间。
wait_timeout
The number of seconds the server waits for activity on a noninteractive connection before closing it. This timeout applies only to TCP/IP and Unix socket file connections, not to connections made via named pipes, or shared memory.

interactive_timeout
The number of seconds the server waits for activity on an interactive connection before closing it. An interactive client is defined as a client that uses the CLIENT_INTERACTIVE option to mysql_real_connect(). See also wait_timeout.

这样就会存在一个问题，如果你的数据库连接池没有设置判断连接是否有效，那么当程序获取连接池中的一个已经被mysql主动关闭的连接时会有抛出异常。
下面给出几个设置示例：
hibernate中的设置

    <property name="hibernate.c3p0.acquire_increment">3</property> 
    <property name="hibernate.c3p0.idle_test_period">5</property> 
    <property name="hibernate.c3p0.timeout">10000</property> 
    <property name="hibernate.c3p0.max_size">80</property> 
    <property name="hibernate.c3p0.min_size">15</property> 
    <property name="hibernate.c3p0.max_statements">0</property>
    <property name="hibernate.c3p0.preferredTestQuery">select 1;</property>

tomcat中设置数据源

testOnBorrow="true" testOnReturn="true" testWhileIdle="true" validationQuery="select 1"