1 public class JdbcUtil2 { 2     //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>
       3     private static LinkedList
      
        connectionspool=new LinkedList
       
        (); 4     //静态代码块 5     static{             6         try { 7             String url="jdbc:mysql://localhost:3306/jdbcdb"; 8             String user="root"; 9             String password="mysql";10             Class.forName("com.mysql.jdbc.Driver");11             //创建3个连接并将它们代理12             for(int i=0;i<3;i++)13             {14                 final Connection conn=DriverManager.getConnection(url, user, password);15                 //对conn进行代理16                 Object proxyobj= Proxy.newProxyInstance(17                         JdbcUtil2.class.getClassLoader(), 18                         new Class[]{Connection.class},19                         new InvocationHandler() {                            20                             public Object invoke(Object proxy, Method method, Object[] args)21                                     throws Throwable {22                                     //是否是close方法23                                     if(method.getName().equals("close"))24                                     {25                                         synchronized(connectionspool){26                                             connectionspool.addLast((Connection)proxy);27                                             connectionspool.notify();28                                         }29                                         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30                                     }31                                     return method.invoke(conn, args);32                             }33                         });34                 35                 connectionspool.add((Connection)proxyobj);36                 37             }38         } catch (SQLException e) {39             // TODO Auto-generated catch block40             e.printStackTrace();41         } catch (ClassNotFoundException e) {42             // TODO Auto-generated catch block43             e.printStackTrace();44         }        45     }46     47     48     public static Connection getConnection()49     {50         synchronized(connectionspool)51         {52             if(connectionspool.size()==0)53             {54                 try {55                     connectionspool.wait();56                 } catch (InterruptedException e) {57                     // TODO Auto-generated catch block58                     e.printStackTrace();59                 }60                 return getConnection();61             }62             else {63                 Connection conn=connectionspool.removeFirst();64                 System.err.println("pool中还有连接数："+connectionspool.size());65                 return conn;66             }67         }68     }    69 }
       
      
     

利用多线程测试代理连接池

1 public class TestProxy  { 2     public static void main(String[] args) { 3         for(int i=0;i<3000;i++) 4         { 5             new MyThread().start(); 6         } 7     } 8 } 9 10 class MyThread extends Thread11 {12     @Override13     public void run() {14         Connection con = null;15         try{16             con = JdbcUtil2.getConnection();17             System.err.println(this.getName()+","+con);18             con.setAutoCommit(false);//设置事务的开始19             String sql = "insert into users values('"+this.getName()+"','Tom','44')";20             Statement st = con.createStatement();21             st.execute(sql);22             con.commit();23             System.err.println(this.getName()+"子线程执行完成。。。。。");24         }catch(Exception e){25             e.printStackTrace();26         }finally{27             try {28                 con.setAutoCommit(true);29                 con.close();30             } catch (SQLException e) {31                 e.printStackTrace();32             }33         }34     }35 }