连接池Connection Pool 单例设计

桃扇骨 2022-06-13 02:28 136阅读 0赞

**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：**

![这里写图片描述][SouthEast]

[SouthEast]: /images/20220613/7139e9eb99f44362845dcbbb35bd65e5.png