java之编写数据库连接池实现连接的复用

 1 package cn.mycast.bank.db;
 2 
 3 import java.sql.Connection;
 4 import java.util.LinkedList;
 5 import cn.mycast.bank.util.JdbcUtil;
 6 public class MyDatabasePool {
 7     private LinkedList<Connection> connPool=new LinkedList<Connection>();//存放连接
 8     public MyDatabasePool(){
 9         for(int i=0;i<10;i++)//连接池中存放10个连接
10         {
11             this.connPool.addLast(this.CreateConnection());//每次添加到集合最后面
12         }
13     }
14     public Connection CreateConnection(){//获得连接
15         return JdbcUtil.getConnection();
16     }
17     public Connection GetConnection(){
18         return connPool.removeFirst();//取出最上面的一个连接
19     }
20     public void FreeConnection(Connection conn){//将用完后的连接放回到集合中
21         this.connPool.addLast(conn);
22     }
23 }

 1 package cn.mycast.bank.util;
 2 
 3 import java.io.IOException;
 4 import java.io.InputStream;
 5 import java.sql.Connection;
 6 import java.sql.DriverManager;
 7 import java.sql.ResultSet;
 8 import java.sql.SQLException;
 9 import java.sql.Statement;
10 import java.util.Properties;
11 
12 import cn.mycast.bank.db.MyDatabasePool;
13 public class JdbcUtil {
14     private static String driver;
15     private static String url;
16     private static String username;
17     private static String password;
18     private static MyDatabasePool connPool;//连接池类
19     static{
20         // 通过类加载器获得资源，并以流的方式进行操作
21         InputStream is=JdbcUtil.class.getClassLoader().getResourceAsStream("cn/mycast/bank/util/Mysqldb.properties");
22         Properties properties=new Properties();
23         try {
24             properties.load(is);
25             url=properties.getProperty("url");
26             driver=properties.getProperty("driver");
27             username=properties.getProperty("username");
28             password=properties.getProperty("password");
29         } catch (IOException e) {
30             e.printStackTrace();
31         }
32     }
33     static{
34         try {
35             Class.forName(driver);//注册驱动
36             connPool=new MyDatabasePool();
37         } catch (ClassNotFoundException e) {
38             e.printStackTrace();
39         }
40     }
41     
42     public static Connection getConnection(){
43         Connection conn=null;
44         try {
45             conn=DriverManager.getConnection(url, username, password);//获得连接
46         } catch (SQLException e) {
47             e.printStackTrace();
48         }finally{
49             
50         }
51         return conn;
52     }
53     public static void close(Connection conn){
54         if(conn!=null)
55             connPool.FreeConnection(conn); //将连接放回集合
56     }
57     public static void close(Statement stm){
58         try {
59             if(stm!=null)
60                 stm.close();
61         } catch (SQLException e) {
62             e.printStackTrace();
63         }
64     }
65     public static void close(ResultSet rs){
66         try {
67             if(rs!=null)
68                 rs.close();
69         } catch (SQLException e) {
70             e.printStackTrace();
71         }
72     }
73 }