C3p0连接池

1.需要导入两个jar包

　　c3p0-0.9.2-pre5.jar

       mchange-commons-java-0.2.3.jar

2.将c3p0-config.xml导入到src根目录下(jar包可以自动加载里面的属性内容)

3.创建数据源ComboPooledDataSource

4.获取连接 getConnection

代码如下:

package c3p0;



import java.sql.Connection;
import java.sql.SQLException;

import javax.sql.DataSource;



import com.mchange.v2.c3p0.ComboPooledDataSource;


public class C3p0Util {
    
    private ComboPooledDataSource dataSource = new ComboPooledDataSource();
    
    //获取数据源
    public ComboPooledDataSource getDataSource(){
        return dataSource;
    }
    
    //获取连接
    public Connection getConnection() throws SQLException{
        return dataSource.getConnection();
    }
    
    public static void main(String[] args) {
        
        try {
            //1.创建数据源
            /**
             * 如果将c3p0-config.xml文件拷贝到src文件夹下
             * 当创建dataSource对象的时候自动加载c3p0-config.xml文件中的<default-config>内容
             * 如果打算使用<named-config name="aa">这个的话,直接将aa作为参数传入
             * ComboPooledDataSource dataSource = new ComboPooledDataSource("aa");
             */
            ComboPooledDataSource dataSource = new ComboPooledDataSource();
            
            //2获取链接
            Connection conn = dataSource.getConnection();
            
            System.out.println(conn);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

<c3p0-config>
    <!-- 默认配置，如果没有指定则使用这个配置 -->
    <default-config>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://127.0.0.1:3306/shop</property>
        <property name="user">root</property>
        <property name="password">1234</property>
        
        <property name="checkoutTimeout">30000</property>
        <property name="idleConnectionTestPeriod">30</property>
        <property name="initialPoolSize">10</property>
        <property name="maxIdleTime">30</property>
        <property name="maxPoolSize">100</property>
        <property name="minPoolSize">10</property>
        <property name="maxStatements">200</property>
        <user-overrides user="test-user">
            <property name="maxPoolSize">10</property>
            <property name="minPoolSize">1</property>
            <property name="maxStatements">0</property>
        </user-overrides>
    </default-config> 
    <!-- 命名的配置 -->
    <named-config name="cc">
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://127.0.0.1:3306/shop</property>
        <property name="user">root</property>
        <property name="password">1234</property>
        <!-- 如果池中数据连接不够时一次增长多少个 -->
        <property name="acquireIncrement">5</property>
        <property name="initialPoolSize">20</property>
        <property name="minPoolSize">10</property>
        <property name="maxPoolSize">40</property>
        <property name="maxStatements">0</property>
        <property name="maxStatementsPerConnection">5</property>
    </named-config>
</c3p0-config>