连接池Connection Pool 单例设计

连接池单例模式

1.私有化ComboPooledDataSource将其作为属性，使其实现单例
2.DataSourceFactory实现懒汉模式,这样作为属性的连接池cpds也就变为了单例
3.从连接池中获取连接Connection

代码如下：

package com.tcb.dao.uitls;

import java.sql.Connection;

import com.mchange.v2.c3p0.ComboPooledDataSource;

/*
 * 连接池单例模式
 * 
 * 1.私有化ComboPooledDataSource将其作为属性，使其实现单例
 * 2.DataSourceFactory实现懒汉模式,这样作为属性的连接池cpds也就变为了单例
 * 3.从连接池中获取连接Connection
 */
public class DataSourceFactory {
    //1.私有化ComboPooledDataSource将其作为属性，使其实现单例
    private ComboPooledDataSource cpds;

    //2.DataSourceFactory实现懒汉模式
    //2.1私有化构造方法--并初始化cpds
    private DataSourceFactory() {
        cpds = new ComboPooledDataSource("c3p0-config");
    }
    //2.2 私有化属性
    private static DataSourceFactory sFactory = null;
    //2.3 返回SessionFactory单例
    public static DataSourceFactory getSessionFactoryInstance() {
        if (sFactory == null) {
            sFactory = new DataSourceFactory();
        }
        return sFactory;
    }

    //3.从连接池中获取连接Connection
    public Connection getSession() throws Exception {
        System.out.println("cpsd========="+cpds);
        Connection connection = cpds.getConnection();
        System.out.println("connection========="+connection);
        return connection;
    }

    public static void main(String[] args) {
        //测试
        DataSourceFactory dataSourceFactory=DataSourceFactory.getSessionFactoryInstance();
        DataSourceFactory dataSourceFactory2=DataSourceFactory.getSessionFactoryInstance();
        try {
            dataSourceFactory.getSession();
            dataSourceFactory.getSession();
            dataSourceFactory.getSession();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

测试结果：