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

  <c3p0-config>
    <default-config>
        <property name="driverClass" >com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl" >jdbc:mysql://localhost:3306/mydb?characterEncoding=GBK</property>
        <property name="user" >root</property>
        <property name="password" ></property>
        
        <property name="maxPoolSize" >15</property>
        <property name="minPoolSize" >5</property>
        <property name="initialPoolSize" >5</property>
    </default-config>
</c3p0-config>  

c3p0.jdbcUrl=jdbc:mysql://localhost:3306/mydb  
c3p0.driverClass=com.mysql.jdbc.Driver    
c3p0.user=root    
c3p0.password= 
    
c3p0.acquireIncrement=3     
c3p0.idleConnectionTestPeriod=60        
c3p0.initialPoolSize=10     
c3p0.maxIdleTime=60     
c3p0.maxPoolSize=20     
c3p0.maxStatements=100      
c3p0.minPoolSize=5    

public static void main(String[] args) throws Exception {
        
        
        
        ComboPooledDataSource cb = new ComboPooledDataSource();
        
        Connection conn=cb.getConnection();
        System.out.println(conn.isClosed());
        conn.close();
        
        
    }

package com.test;

import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Calendar;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class Test {

    public static void main1111(String[] args) throws Exception {
        long start = Calendar.getInstance().getTimeInMillis();
        for(int i=0; i<100;i++){
        Class.forName("com.mysql.jdbc.Driver");
        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb","root","");
        System.out.println(conn.isClosed());
        conn.close();
        }
        long end = Calendar.getInstance().getTimeInMillis();
        System.out.println(end-start);
    }
    public static void main(String[] args) throws Exception {
        
        long start = Calendar.getInstance().getTimeInMillis();
        
        ComboPooledDataSource cb = new ComboPooledDataSource();
        for(int i=0; i<100;i++){
        Connection conn=cb.getConnection();
        System.out.println(conn.isClosed());
        conn.close();
        }
        long end = Calendar.getInstance().getTimeInMillis();
        System.out.println(end-start);
    }

}

public static void main11(String[] args) throws Exception {
        ComboPooledDataSource cd = new ComboPooledDataSource();
        cd.setDriverClass("com.mysql.jdbc.Driver");
        cd.setJdbcUrl("jdbc:mysql://localhost:3306/mydb");
        cd.setUser("root");
        cd.setPassword("");
        cd.setMinPoolSize(5);
        cd.setMaxPoolSize(10);
        Connection conn = cd.getConnection();
        System.out.println(conn.isClosed());
        conn.close();

    }

driverClass=com.mysql.jdbc.Driver
jdbcUrl=jdbc:mysql://localhost:3306/mydb?characterEncoding=GBK
user=root
password=

minPoolSize=5
maxPoolSize=15
initialPoolSize=5

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">
    
    <context:property-placeholder location="classpath:db.properties"/>
    
    <bean class="com.mchange.v2.c3p0.ComboPooledDataSource" id="dataSource">
        <property name="driverClass" value="${driverClass}"></property>
        <property name="jdbcUrl" value="${jdbcUrl}"></property>
        <property name="user" value="${user}"></property>
        <property name="password" value="${password}"></property>
        
        <property name="minPoolSize" value="${minPoolSize}"></property>
        <property name="maxPoolSize" value="${maxPoolSize}"></property>
        <property name="initialPoolSize" value="${initialPoolSize}"></property>
    </bean>
    
</beans>

public static void main3333(String[] args) throws Exception {
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        DataSource d = (DataSource)context.getBean("dataSource");
        Connection conn = d.getConnection();
        System.out.println(conn.isClosed());
        conn.close();
    }