Proxool连接池完成一个简单的例子

很多读者朋友都觉得连接池很神秘，本例将采用Proxool连接池完成一个简单的例子。大家可以到http://proxool.sourceforge.net下载连接池包，下载完成后把proxool-0.9.0RC3.jar(位于Lib下).。

 

       新建一个web或java工程，为工程设置Hibernate环境（将所相关的jar包添加到工程之中）建立一个proxool.xml文件，将这个文档置于src目录之中：

<?xml version="1.0" encoding="UTF-8"?>

<!-- the proxool configuration can be embedded within your own application's.

       Anything outside the "proxool" tag is ignored. -->

<something-else-entirely>

       <proxool>

              <alias>mysql</alias>

              <driver-url>jdbc:mysql://localhost:3306/tdjob</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>60000</house-keeping-sleep-time>

              <proxool.simultaneous-build-throttle>

                     100

              </proxool.simultaneous-build-throttle>

              <prototype-count>2</prototype-count>

              <maximum-connection-count>100</maximum-connection-count>

              <minimum-connection-count>10</minimum-connection-count>

       </proxool>

</something-else-entirely>

       现在来看下配置的意思：

       <alias>配置连接池的别名；

       <driver-url>和写JDBC连接数据库时的URL一样。

       <driver-class>和写JDBC连接数据库时的Driver一样。

       <driver-properies>就是连接数据库时的用户名和密码。

       <house-keeping-sleep-time>proxool自动侦察各个连接状态的时间间隔(毫秒),侦察到空闲的连接就马上回收，超时的销毁。

       <prototype-count>最少保持的空闲连接数

       <maximum-connection-count>最大连接数。

       <minimum-connection-count>最小连接数。

       以下是在Hibernate配置文件中对连接池的配置：

<?xml version='1.0' encoding='UTF-8'?>

<!DOCTYPE hibernate-configuration PUBLIC

          "-//Hibernate/Hibernate Configuration DTD 3.0//EN"

          "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

 

<!-- Generated by MyEclipse Hibernate Tools. -->

<hibernate-configuration>

       <session-factory>

<!-- proxool连接池加载的类-->

 

              <property name="hibernate.connection.provider_class">

                     org.hibernate.connection.ProxoolConnectionProvider

              </property>

  <!--连接池文件的地址-->

 

              <property name="hibernate.proxool.xml">proxool.xml</property>

<!--连接池的别名，即配置连接池时起的别名-->

              <property name="hibernate.proxool.pool_alias">mysql</property>

  <!--是否将运行期生成的SQL输出到日志以供调试-->

  <property name="show_sql">true</property>

              <mapping resource="com/xmh/domain/User.hbm.xml" />

       </session-factory>

</hibernate-configuration>

       新建一个实体文件：

package com.xmh.domain;

 

/**

 * Admins generated by MyEclipse Persistence Tools

 */

 

public class User implements java.io.Serializable {

 

       // Fields

 

       private Integer id;

       private String name;

       private Integer age;

       public Integer getId() {

              return id;

       }

       ……

             

}

       创建一个映射文件：

<?xml version="1.0" encoding="utf-8"?>

<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"

"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<!--

    Mapping file autogenerated by MyEclipse Persistence Tools

-->

<hibernate-mapping>

    <class name="com.xmh.domain.User" table="td_user">

        <id name="id" type="java.lang.Integer">

            <column name="id" />

            <generator class="native" />

        </id>

        <property name="name" type="java.lang.String">

            <column name="name" length="20" />

        </property>

        <property name="age" type="java.lang.Integer">

            <column name="age" length="30" />

        </property>

    </class>

</hibernate-mapping>

 

       编写测试文件：

package com.xmh.domain;

 

import java.util.List;

import org.apache.log4j.Logger;

import org.hibernate.Query;

import org.hibernate.Session;

 

import com.xmh.factory.HibernateSessionFactory;

public class Test {

       /**

        * @param args

        */

       public static void main(String[] args) {

              Logger log = Logger.getLogger(Teest.class);

              Session session = HibernateSessionFactory.getSession();

              String sqlstr = "from User u where u.id>:id";

              try {

                     Query query = session.createQuery(sqlstr);

                     query.setInteger("id", 1);

                     List list = query.list();

                     log.info("the list's size are: "+list.size());

              } catch (Exception e) {

                     log.error("is error!!!!");

                     log.error(e.getMessage());

              }

       }

}