动态代理写connection连接池Demo

 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<Connection> connectionspool=new LinkedList<Connection>();
 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 block
40             e.printStackTrace();
41         } catch (ClassNotFoundException e) {
42             // TODO Auto-generated catch block
43             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 block
58                     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 Thread
11 {
12     @Override
13     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 }