使用代理创建连接池 proxyPool

配置文件properties

 url=jdbc:mysql://127.0.0.1:3306/mine?characterEncoding=UTF-8

user=root

password=1234

driverClass=com.mysql.jdbc.Driver 

主要代码

package JDBCUtils;

import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.LinkedList;
import java.util.Properties;
/**
 * 使用代理创建连接池
 * @author ASUS
 *
 */
public class ProxyConnUtils {

    private static LinkedList<Connection> pool =  new LinkedList<>();
    private static String url;
    private static String user;
    private static String password;
    private static String driverClass;
    //private static Connection conn;
    static{
        try {
            Properties properties = new Properties();
            InputStream in = ProxyConnUtils.class.getResourceAsStream("/db.properties");
            properties.load(in);
            url = properties.getProperty("url");
            System.err.println(url);
            user = properties.getProperty("user");
            password = properties.getProperty("password");
            driverClass = properties.getProperty("driverClass");
            Class.forName(driverClass);
            for(int i = 0;i<3;i++){
                final Connection conn = DriverManager.getConnection(url, user, password);
                //对connection做代理
                Object connProxy = Proxy.newProxyInstance(ProxyConnUtils.class.getClassLoader(),
                    new Class[]{Connection.class},
                    new InvocationHandler() {
                        
                        @Override
                        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                            //判断是否是close方法   回收连接
                            if(method.getName().equals("close")){
                                synchronized (pool) {
                                    System.err.println("不能关闭");
                                    pool.addLast((Connection) proxy);
                                    pool.notify();
                                    return null;
                                }
                            }else{
                                //若果调用的不是close方法  直接放行
                                return method.invoke(conn, args);
                            }
                        }
                    });
                // 将代理对象添加到池中去
                pool.add((Connection) connProxy);
            }
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        } 
    }
    
    //获取connection连接
    public static Connection getConnection(){
        synchronized (pool) {
            if(pool.size() == 0){
                try {
                    pool.wait();
                } catch (Exception e) {
                    e.printStackTrace();
                    throw new RuntimeException(e);
                }
            }
            Connection connection = pool.removeFirst();
            return connection;
        }
    }
}

测试代码

package JDBCTest;
import java.sql.Connection;
import java.sql.Statement;
import java.util.Scanner;
import JDBCUtils.ConnUtil;
import JDBCUtils.ConnUtils;
import JDBCUtils.ProxyConnUtils;
public class Demo01_tx3 {
    class one extends Thread{
        @Override
        public void run() {
            System.err.println("1:获取连接");
            Connection con = 
                    ProxyConnUtils.getConnection();
            try{
                System.err.println("2:打开事务");
                con.setAutoCommit(false);
                System.err.println("3:写入Jack");
                Statement st = con.createStatement();
                st.execute("insert into money(id,name) values(1,'Jack')");
                System.err.println("4:提交  ..");
                con.commit();
            }catch(Exception e){
                e.printStackTrace();
            }finally {
                try {
                    System.err.println("5:关闭连接");
                    con.setAutoCommit(true);
                    con.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        };
    };
    
    public Demo01_tx3() {
        for(int i=0;i<5;i++){
            new one().start();
        }
    }

    public static void main(String[] args) {
        new Demo01_tx3();
    }
}

运行结果