1 package me.gacl.demo; 2 3 import java.io.InputStream; 4 import java.io.PrintWriter; 5 import java.lang.reflect.InvocationHandler; 6 import java.lang.reflect.Method; 7 import java.lang.reflect.Proxy; 8 import java.sql.Connection; 9 import java.sql.DriverManager; 10 import java.sql.SQLException; 11 import java.util.LinkedList; 12 import java.util.Properties; 13 import javax.sql.DataSource; 14 15 /** 16 * @ClassName: JdbcPool 17 * @Description:编写数据库连接池 18 * @author: 孤傲苍狼 19 * @date: 2014-9-30 下午11:07:23 20 * 21 */ 22 public class JdbcPool implements DataSource{ 23 24 /** 25 * @Field: listConnections 26 * 使用LinkedList集合来存放数据库链接, 27 * 由于要频繁读写List集合,所以这里使用LinkedList存储数据库连接比较合适 28 */ 29 private static LinkedList<Connection> listConnections = new LinkedList<Connection>(); 30 31 static{ 32 //在静态代码块中加载db.properties数据库配置文件 33 InputStream in = JdbcPool.class.getClassLoader().getResourceAsStream("db.properties"); 34 Properties prop = new Properties(); 35 try { 36 prop.load(in); 37 String driver = prop.getProperty("driver"); 38 String url = prop.getProperty("url"); 39 String username = prop.getProperty("username"); 40 String password = prop.getProperty("password"); 41 //数据库连接池的初始化连接数大小 42 int jdbcPoolInitSize =Integer.parseInt(prop.getProperty("jdbcPoolInitSize")); 43 //加载数据库驱动 44 Class.forName(driver); 45 for (int i = 0; i < jdbcPoolInitSize; i++) { 46 Connection conn = DriverManager.getConnection(url, username, password); 47 System.out.println("获取到了链接" + conn); 48 //将获取到的数据库连接加入到listConnections集合中,listConnections集合此时就是一个存放了数据库连接的连接池 49 listConnections.add(conn); 50 } 51 52 } catch (Exception e) { 53 throw new ExceptionInInitializerError(e); 54 } 55 } 56 57 @Override 58 public PrintWriter getLogWriter() throws SQLException { 59 // TODO Auto-generated method stub 60 return null; 61 } 62 63 @Override 64 public void setLogWriter(PrintWriter out) throws SQLException { 65 // TODO Auto-generated method stub 66 67 } 68 69 @Override 70 public void setLoginTimeout(int seconds) throws SQLException { 71 // TODO Auto-generated method stub 72 73 } 74 75 @Override 76 public int getLoginTimeout() throws SQLException { 77 // TODO Auto-generated method stub 78 return 0; 79 } 80 81 @Override 82 public <T> T unwrap(Class<T> iface) throws SQLException { 83 // TODO Auto-generated method stub 84 return null; 85 } 86 87 @Override 88 public boolean isWrapperFor(Class<?> iface) throws SQLException { 89 // TODO Auto-generated method stub 90 return false; 91 } 92 93 /* 获取数据库连接 94 * @see javax.sql.DataSource#getConnection() 95 */ 96 @Override 97 public Connection getConnection() throws SQLException { 98 //如果数据库连接池中的连接对象的个数大于0 99 if (listConnections.size()>0) { 100 //从listConnections集合中获取一个数据库连接 101 final Connection conn = listConnections.removeFirst(); 102 System.out.println("listConnections数据库连接池大小是" + listConnections.size()); 103 //返回Connection对象的代理对象 104 return (Connection) Proxy.newProxyInstance(JdbcPool.class.getClassLoader(), conn.getClass().getInterfaces(), new InvocationHandler(){ 105 @Override 106 public Object invoke(Object proxy, Method method, Object[] args) 107 throws Throwable { 108 if(!method.getName().equals("close")){ 109 return method.invoke(conn, args); 110 }else{ 111 //如果调用的是Connection对象的close方法,就把conn还给数据库连接池 112 listConnections.add(conn); 113 System.out.println(conn + "被还给listConnections数据库连接池了!!"); 114 System.out.println("listConnections数据库连接池大小为" + listConnections.size()); 115 return null; 116 } 117 } 118 }); 119 }else { 120 throw new RuntimeException("对不起,数据库忙"); 121 } 122 } 123 124 @Override 125 public Connection getConnection(String username, String password) 126 throws SQLException { 127 return null; 128 } 129 }
数据库连接池
最新推荐文章于 2025-04-06 11:38:38 发布