1、相關jar包，這裡需要3個jar包

2、具體連結資料庫程式碼

        ComboPooledDataSource類繼承自AbstractComboPooledDataSource類，且AbstractComboPooledDataSource類實現了PooledDataSource介面

ComboPooledDataSource常用方法

（1）、通過ComboPooledDataSource類直接建立資料來源物件

Example4.java

import com.mchange.v2.c3p0.ComboPooledDataSource;
import javax.sql.DataSource;
import java.sql.SQLException;
public class Example4{
    public static DataSource dataSource = null;
    //初始化C3P0資料來源
    static {
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
        try{
            comboPooledDataSource.setDriverClass("com.mysql.jdbc.Driver");
            comboPooledDataSource.setJdbcUrl("jdbc:mysql://127.0.0.1:3306/chapter02");
            comboPooledDataSource.setUser("root");
            comboPooledDataSource.setPassword("1234");
            //初始化
            comboPooledDataSource.setInitialPoolSize(5);
            //設定最大的連結數
            comboPooledDataSource.setMaxPoolSize(15);
            dataSource = comboPooledDataSource;
        }catch (Exception e){
        }
    }
    public static void main(String[] args)throws SQLException {
        System.out.println(dataSource.getConnection());
    }
}
 

（2）、通過配置檔案建立資料來源物件

        在專案的src目錄下建立一個出c3p0-donfig.xml檔案

c3p0-donfig.xml內容如下

<?xml version="1.0" encoding="utf-8" ?>
<c3p0-config>
    <default-config>
        <property name="user">root</property>
        <property name="password">1234</property>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">
            jdbc:mysql://localhost:3306/chapter02
        </property>
        <property name="checkoutTimeout">30000</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>
    </default-config>
    <named-config name="dongyao">
        <property name="initialPoolSize">5</property>
        <property name="maxPoolSize">15</property>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">
            jdbc:mysql://localhost:3306/chapter02
        </property>
        <property name="user">root</property>
        <property name="password">1234</property>
    </named-config>
</c3p0-config>

         其中<default-config>是預設配置，<named-config name=””>是自定義配置，一個配置檔案中可以有一個或者多個自定義配置，呼叫ComboPoolDataSource(String configName)方法傳入<named-config>節點中name屬性的值即可建立C3P0資料來源物件。

         在專案的src目錄下建立一個Example5的類

Example5.java

import com.mchange.v2.c3p0.ComboPooledDataSource;

import javax.sql.DataSource;
import java.sql.SQLException;

public class Example5 {
    public static DataSource dataSource = null;
    static {
        ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource("dongyao");
        dataSource = comboPooledDataSource;
    }
    public static void main(String[] args) throws SQLException {
        System.out.println(dataSource.getConnection());
    }
}

3、控制檯顯示