hibernate3连接池

1．Hibernate默认连接池
<!---->
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!---->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<!---->
<property name="connection.url">
jdbc:mysql://localhost:3306/schoolproject
</property>
<property name="connection.useUnicode">true</property>
<property name="connection.characterEncoding">UTF-8</property>
<!---->
<property name="connection.username">root</property>
<!---->
<property name="connection.password"></property>
<!---->
<property name="show_sql">true</property>
<!---->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!---->
<mapping resource="com/wqbi/model/pojo/student.hbm.xml">
</session-factory>
</hibernate-configuration>


2．C3P0连接配置
<!---->
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!---->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<!---->
<property name="connection.url">
jdbc:mysql://localhost:3306/schoolproject
</property>
<property name="connection.useUnicode">true</property>
<property name="connection.characterEncoding">UTF-8</property>
<!---->
<property name="connection.username">root</property>
<!---->
<property name="connection.password"></property>
<!---->
<property name="hibernate.connection.provider_class">
org.hibernate.connection.C3P0ConnectionProvider
</property>
<property name="hibernate.c3p0.max_size">20</property>
<property name="hibernate.c3p0.min_size">5</property>
<property name="hibernate.c3p0.timeout">120</property>
<property name="hibernate.c3p0.max_statements">100</property>
<property name="hibernate.c3p0.idle_test_period">120</property>
<property name="hibernate.c3p0.acquire_increment">2</property>
<!---->
<property name="show_sql">true</property>
<!---->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!---->
<mapping resource="com/wqbi/model/pojo/student.hbm.xml">
</session-factory>
</hibernate-configuration>


3．proxool连接池
(1) 先写proxool的配置文件，文件名：proxool.xml（一般放在与hibernate.cfg.xml文件在同一个目录中）本例配置的是MYSQL数据库，数据库的名字为schoolproject
<!---->
<!---->
<something-else-entirely>
<proxool>
<!---->
<alias>DBPool</alias>
<!---->
<driver-url>
jdbc:mysql://localhost:3306/schoolproject?useUnicode=true&characterEncoding=UTF8
</driver-url>
<!---->
<driver-class>com.mysql.jdbc.Driver</driver-class>
<driver-properties>
<property name="user" value="root">
<property name="password" value="">
</driver-properties>
<!---->
<house-keeping-sleep-time>90000</house-keeping-sleep-time>
<!---->
<maximum-new-connections>20</maximum-new-connections>
<!---->
<prototype-count>5</prototype-count>
<!---->
<maximum-connection-count>100</maximum-connection-count>
<!---->
<minimum-connection-count>10</minimum-connection-count>
</proxool>
</something-else-entirely>

(2)配置hibernate.cfg.xml文件
<!---->
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.provider_class">
org.hibernate.connection.ProxoolConnectionProvider
</property>
<property name="hibernate.proxool.pool_alias">DBPool</property>
<property name="hibernate.proxool.xml">proxoolconf.xml</property>
<!---->
<property name="show_sql">true</property>
<!---->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!---->
<mapping resource="com/wqbi/model/pojo/student.hbm.xml">
</session-factory>
</hibernate-configuration>
(1) hibernate.connection.provider_class定义Hibernate的连接加载类，这里Proxool连接池是用这个
，不同的连接池有不同的加载类，可以查阅Hibernate文档获取相关信息
(2) hibernate.proxool.pool_alias这里就是用我们上面提到的连接池的别名
(3) hibernate.proxool.xml是向Hibernate声明连接池的配置文件位置，可以用相对或绝对路径，用相对路径时要注意一定在要Path范围内！不然会抛出异常。
(4) dialect是声明ＳＱＬ语句的方言
(5) show_sql定义是否显示Hibernate生成的ＳＱＬ语言，一般在调试阶段设为true,完成后再改成false，这样有利于调试。
(6) <mapping>资源文件映射

4．JNDI连接池，数据源已经由应用服务配置好(如Web服务器)，Hibernate需要做的只是通过JNDI名查找到此数据源。应用服务器将连接池对外显示为JNDI绑定数据源，它是javax.jdbc.Datasource类的一个实例。只要配置一个Hibernate文件，如：

hibernate.connection.datasource=java:/comp/env/jdbc/schoolproject //JNDI名
hibernate.transaction.factory_class = org.hibernate.transaction.JTATransactionFactory
hibernate.transaction.manager_loopup_class = org.hibernate.transaction.JBossTransactionManagerLookup
hibernate.dialect=org.hibernate.dialect.MySQLDialect