动态代理写connection连接池Demo

public class JdbcUtil2 {
    //声明连接池<放到LinkedList中，操作其中对象的速度快 只需要改变连接>
    private static LinkedList<Connection> connectionspool=new LinkedList<Connection>();
    //静态代码块
    static{            
        try {
            String url="jdbc:mysql://localhost:3306/jdbcdb";
            String user="root";
            String password="mysql";
            Class.forName("com.mysql.jdbc.Driver");
            //创建3个连接并将它们代理
            for(int i=0;i<3;i++)
            {
                final Connection conn=DriverManager.getConnection(url, user, password);
                //对conn进行代理
                Object proxyobj= Proxy.newProxyInstance(
                        JdbcUtil2.class.getClassLoader(), 
                        new Class[]{Connection.class},
                        new InvocationHandler() {                            
                            public Object invoke(Object proxy, Method method, Object[] args)
                                    throws Throwable {
                                    //是否是close方法
                                    if(method.getName().equals("close"))
                                    {
                                        synchronized(connectionspool){
                                            connectionspool.addLast((Connection)proxy);
                                            connectionspool.notify();
                                        }
                                        return null;//如果调用的是close()方法，不会调用代理类的方法，会调用代理
                                    }
                                    return method.invoke(conn, args);
                            }
                        });
                
                connectionspool.add((Connection)proxyobj);
                
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }        
    }
    
    
    public static Connection getConnection()
    {
        synchronized(connectionspool)
        {
            if(connectionspool.size()==0)
            {
                try {
                    connectionspool.wait();
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                return getConnection();
            }
            else {
                Connection conn=connectionspool.removeFirst();
                System.err.println("pool中还有连接数："+connectionspool.size());
                return conn;
            }
        }
    }    
}

利用多线程测试代理连接池

public class TestProxy  {
    public static void main(String[] args) {
        for(int i=0;i<3000;i++)
        {
            new MyThread().start();
        }
    }
}

class MyThread extends Thread
{
    @Override
    public void run() {
        Connection con = null;
        try{
            con = JdbcUtil2.getConnection();
            System.err.println(this.getName()+","+con);
            con.setAutoCommit(false);//设置事务的开始
            String sql = "insert into users values('"+this.getName()+"','Tom','44')";
            Statement st = con.createStatement();
            st.execute(sql);
            con.commit();
            System.err.println(this.getName()+"子线程执行完成。。。。。");
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            try {
                con.setAutoCommit(true);
                con.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}