1、相关jar包，这里需要3个jar包
2、具体链接数据库代码
ComboPooledDataSource类继承自AbstractComboPooledDataSource类，且AbstractComboPooledDataSource类实现了PooledDataSource接口
ComboPooledDataSource常用方法
（1）、通过ComboPooledDataSource类直接创建数据源对象
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数据源
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);
//设置最大的链接数
comboPooledDataSource.setMaxPoolSize(15);
dataSource = comboPooledDataSource;
}catch (Exception e){
}
}
public static void main(String[] args)throws SQLException {
System.out.println(dataSource.getConnection());
}
}
（2）、通过配置文件创建数据源对象
在项目的src目录下创建一个出c3p0-donfig.xml文件
c3p0-donfig.xml内容如下
<?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>是默认配置，<named-config name=””>是自定义配置，一个配置文件中可以有一个或者多个自定义配置，调用ComboPoolDataSource(String configName)方法传入<named-config>节点中name属性的值即可创建C3P0数据源对象。
在项目的src目录下创建一个Example5的类
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、控制台显示
