where should c3p0 properties specified?

问题

I am using spring/hibernate integrated application. I have configured c3p0 connection pooling. I am using c3p0 combopooled datasource. Where should I specify combopooled datasource properties?

In this section?

<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
        <property name="mappingLocations" value="classpath:hibernate-mapping.xml" />
        <property name="hibernateProperties">
            <props>
                **//Here do I need to specify combopooled datasource properties?
        //like acquireIncrement
            acquireRetryAttempts
            acquireRetryDelay
            preferredTestQuery
            maxPoolSize...etc**
            </props>
        </property>
        <property name="dataSource" ref="dataSource" />
    </bean>

Or here?

<bean id="rootDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${jdbc.driver}" />
        <property name="jdbcUrl" value="${jdbc.url}" />
        <property name="user" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
**//Here do i need to specify combopooled datasource properties?
            //like acquireIncrement
            acquireRetryAttempts
            acquireRetryDelay
            preferredTestQuery**
            maxPoolSize...etc

</bean>

Please suggest me.

Thanks!

回答1:

You can specify them in a c3p0.properties file. Just place it in the root of your classpath

or, in xml file named c3p0-config.xml also in the root of your classpath

or, if you want it in you spring xml for Hibernate you can use

<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
      <!--<property name="lobHandler">
         <ref local="lobHandler" />
      </property>-->
      <property name="hibernateProperties">
         <props>
            <prop key="hibernate.connection.driver_class">${jdbc.drivers}</prop>
            <prop key="hibernate.connection.url">${jdbc.url}</prop>
            <prop key="hibernate.connection.username">${jdbc.username}</prop>
            <prop key="hibernate.connection.password">${jdbc.password}</prop>
            <prop key="hibernate.c3p0.min_size">5</prop>
            <prop key="hibernate.c3p0.max_size">100</prop>
            <prop key="hibernate.c3p0.timeout">1800</prop>
            <prop key="hibernate.c3p0.max_statements">50</prop>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</prop>
            <prop key="hibernate.cglib.use_reflection_optimizer">true</prop>
            <prop key="hibernate.show_sql">true</prop>
            <prop key="hibernate.format_sql">true</prop>
         </props>
      </property>

I believe the Hibernate settings override the use of a c3po.properties file if both exist. however this post suggests some inconsistencies with the c3po docs

回答2:

Those should go on to the data source bean (rootDataSource). Once you pass a data source to the LocalSessionFactoryBean hibernate will not be creating the connection pool - so the properties specified under hibernateProperties will be ignored.

All the properties you want to set are available as setter methods on ComboPooledDataSource. Add more property tags to your data source bean and specify the value for those there.

<bean id="rootDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${jdbc.driver}" />
        <property name="jdbcUrl" value="${jdbc.url}" />
        <property name="user" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
        <property name="password" value="${jdbc.password}" />
        <property name="acquireRetryAttempts" value="..." />
        <property name="acquireRetryDelay" value="..." />
        <property name="preferredTestQuery" value="..." />
        <property name="maxPoolSize" value="..." />    
    </bean>

来源：https://stackoverflow.com/questions/10553797/where-should-c3p0-properties-specified