Question

我正在尝试为网站设置hibernate的c3p0连接池。在MS SQL数据库中运行选定数量的连接我看到min_size属性中指定的双重连接数。看了一下日志，我发现连接池似乎被初始化了两次。有谁知道它为什么会发生？

日志：

[INFO] c3p0.C3P0Registry Initializing c3p0-0.9.1 [built 16-January-2007 14:46:42; 
debug? true; trace: 10]
[INFO] impl.AbstractPoolBackedDataSource Initializing c3p0 pool... 
com.mchange.v2.c3p0.PoolBackedDataSource@bb009603 [ connectionPoolDataSource -> 
com.mchange.v2.c3p0.WrapperConnectionPoolDataSource@6dd5f639 [ acquireIncrement -> 3, 
acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, .......

在这几行之后我们又来了：

[INFO] impl.AbstractPoolBackedDataSource Initializing c3p0 pool... 
com.mchange.v2.c3p0.PoolBackedDataSource@fbb6bb58 [ connectionPoolDataSource -> 
com.mchange.v2.c3p0.Wrap......

我的Hibernate属性（部分）：

<property name="hibernate.connection.driver_class">net.sourceforge.jtds.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:jtds:sqlserver://192.168.0.67:1433/SSS2;instanceName=SQLEXPRESS;</property>
<property name="hibernate.dialect">org.hibernate.dialect.SQLServerDialect</property>
<property name="hibernate.connection.username">DEV</property>
<property name="hibernate.connection.password">123</property>
<property name="hbm2ddl.auto">validate</property>

<property name="hibernate.cache.use_second_level_cache">true</property>
<property name="hibernate.cache.region.factory_class">net.sf.ehcache.hibernate.SingletonEhCacheRegionFactory</property>

<property name="hibernate.show_sql">true</property>
<property name="hibernate.format_sql">true</property>

<property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
<property name="hibernate.c3p0.min_size">6</property>
<property name="hibernate.c3p0.max_size">10</property>
<property name="hibernate.c3p0.timeout">300</property>


<property name="hibernate.c3p0.max_statements">0</property>
<property name="hibernate.c3p0.idle_test_period">100</property>

<mapping class="***.entities.User" />
<mapping class="***.entities.UserRole" />
<mapping class="***.entities.AccountType" />

Maven POM（部分）：

<dependency>
    <groupId>org.apache.tapestry</groupId>
    <artifactId>tapestry-hibernate</artifactId>
    <version>${tapestry-release-version}</version>
</dependency>

<!-- Hibernate c3p0 connection pool -->
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-c3p0</artifactId>
    <version>${hibernate-c3p0-version}</version>
</dependency>

-------
<tapestry-release-version>5.3.3</tapestry-release-version>
<hibernate-c3p0-version>3.6.0.Final</hibernate-c3p0-version>

我使用会话工厂创建每个事务的hibernate会话，并在try-catch语句的finally块中关闭它。（如果需要，HibernateFactory只需构建工厂并打开会话）

protected <T> List <T> findAll(Class<T> clazz) {
    List <T> objects = null;
    Session session = HibernateFactory.openSession();
    Transaction tx = session.beginTransaction();
    try {   
        Query query = session.createQuery("from "+clazz.getName()+" as user left join fetch user.userRole");            
        objects = query.list();
        tx.commit();
    } catch (HibernateException e) {
        handleException(e, tx);
    } finally {
        HibernateFactory.close(session);
    }
    return objects;
}

Hibernate c3p0连接池初始化两次

1 个答案: