c3p0 连接池未关闭连接

Question

我有一个 Using c3p0 0.9.1.2 ，hibernate 3.2.1.ga 和 spring 2.5.5。问题是数据库连接不会自行关闭。以下是日志：

[2012 年 3 月 22 日 12:29:56,091] 调试 com.mchange.v2.resourcepool.BasicResourcePool ["http-apr-8080"-exec-4] 获取测试 -- 池已满。 [管理：20；最大：20] [2012 年 3 月 22 日 12:29:56,091] 调试 com.mchange.v2.resourcepool.BasicResourcePool ["http-apr-8080"-exec-4] awaitAvailable(): com.mchange.v2.c3p0.impl.NewPooledConnection@15cc604 [2012 年 3 月 22 日 12:29:56,091] 调试 com.mchange.v2.resourcepool.BasicResourcePool ["http-apr-8080"-exec-4] 跟踪 com.mchange.v2.resourcepool.BasicResourcePool@6b0524 [管理：20，未使用：0，排除：0]（例如 com.mchange.v2.c3p0.impl.NewPooledConnection@15cc604）

这是数据源配置：

<!-- Local DataSource that works in any environment -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
    <property name="driverClass" value="${database.driver}"/>
    <property name="jdbcUrl" value="${database.url}"/>
    <property name="user" value="${database.user}"/>
    <property name="password" value="${database.password}"/>
    <!--<property name="connectionCustomizerClassName" value="org.xxx.webapp.common.persistence.WatchConnectionCustomizer"/>-->
    <property name="maxStatements" value="500"/>
    <property name="maxIdleTime" value="1800"/>
    <property name="maxPoolSize" value="100"/>
    <property name="minPoolSize" value="2"/>
    <property name="initialPoolSize" value="2"/>
    <property name="acquireIncrement" value="3"/>
    <property name="idleConnectionTestPeriod" value="3000"/>
</bean>



<bean id="sessionFactory"
    class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean" >
    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.dialect">${hibernate.dialect}</prop>
            <prop key="hibernate.show_sql">false</prop>
            <prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>
            <prop key="hibernate.connection.autocommit">${hibernate.connection.autocommit}</prop>
            <prop key="hibernate.transaction.auto_close_session">${hibernate.transaction.auto_close_session}</prop>
            <prop key="hibernate.connection.release_mode">${hibernate.connection.release_mode}</prop>
            <prop key="hibernate.bytecode.use_reflection_optimizer">${hibernate.bytecode.use_reflection_optimizer}</prop>
            <prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</prop>
            <prop key="hibernate.cache.use_query_cache">true</prop>
            <prop key="hibernate.cache.use_second_level_cache">true</prop>
            <prop key="hibernate.cache.region.factory_class">net.sf.ehcache.hibernate.EhCacheRegionFactory</prop>
        </props>
    </property>

 <property name="annotatedClasses">
    <list>
        ...
   </list>
    </property>

   <property name="dataSource">
    <ref bean="dataSource" />
   </property>


</bean>

<bean id="transactionManager"
    class="org.springframework.orm.hibernate3.HibernateTransactionManager">
    <property name="sessionFactory">
        <ref bean="sessionFactory" />
    </property>
</bean>

这是我们的通用道

public class GenericDAO<T, PK extends Serializable> extends HibernateDaoSupport
    implements IGenericDAO<T, PK> {

private Class<T> clazz;
private Logger logger = Logger.getLogger(GenericDAO.class);
private static Session session;

public GenericDAO(Class<T> clazz) {
    this.clazz = clazz;
}

public void refresh(T instanceToRefresh) throws DataAccessException {
    getHibernateTemplate().refresh(instanceToRefresh);
    //getCurrentSession().refresh(instanceToRefresh);
}

public void saveOrUpdate(T instanceToSaveOrUpdate)
        throws DataAccessException {
    //getCurrentSession().saveOrUpdate(instanceToSaveOrUpdate);
    getHibernateTemplate().saveOrUpdate(instanceToSaveOrUpdate);
}

public void persist(T instanceToPersist) throws DataAccessException {
    getHibernateTemplate().persist(instanceToPersist);
    //getCurrentSession().persist(instanceToPersist);
}

@SuppressWarnings("unchecked")
public T merge(T instanceToMerge) throws DataAccessException {
    T instanceMerged = (T) getHibernateTemplate().merge(instanceToMerge);
    //T instanceMerged = (T) getCurrentSession().merge(instanceToMerge);
    return instanceMerged;
}

@SuppressWarnings("unchecked")
public PK save(T newInstance) throws DataAccessException {
    return (PK) getHibernateTemplate().save(newInstance);
    //return (PK) getCurrentSession().save(newInstance);
}

public void delete(T persistentObject) throws DataAccessException {
    getHibernateTemplate().delete(persistentObject);
    //getCurrentSession().delete(persistentObject);
}

@SuppressWarnings("unchecked")
public T load(PK id) {
    return (T) getHibernateTemplate().get(clazz, id);
    //return (T) getCurrentSession().get(clazz, id);
}

public void update(T transientObject) throws DataAccessException {
    //getCurrentSession().update(transientObject);
    getHibernateTemplate().update(transientObject);
}

@SuppressWarnings("unchecked")
public List<T> loadAll() throws DataAccessException {
    //Session session = this.getCurrentSession();
    //return session.createQuery("from " + clazz.getName()).list();
    return getHibernateTemplate().loadAll(clazz);
}
}

提前致谢。

Answer 1

通常，连接会被休眠自动关闭。不过有几点需要注意：

• 长时间运行的事务可能会占用一个连接
• 不正确的会话管理可能意味着您没有关闭会话，这反过来又意味着连接仍在使用中

使用 spring 时的典型设置是使用 @Transactional 注释您的服务方法。这样，spring 将管理您的事务和会话。

Answer 2

我们在dispatcher-servlet.xml 文件中使用了以下行，数据库物理连接现在正在关闭。

<tx:annotation-driven proxy-target-class="true" transaction-manager="transactionManager"/>