连接池代码

import java.util.HashMap;
import java.util.Vector;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.*;

/**
 * Title:
 * Description: test
 *
 * Copyright: Copyright (c) 2003
 *
 * Company: home
 *
 * @author dalong
 * @version 1.0
 */

public class ConnectionPool
{

 // 连接池的管理器,首先初始化，仅仅有一个对象，管理连接池
 private static HashMap connectionPoolManager = new HashMap();
 // 没有用过的连接池，用vector实现同步
 private static Vector noUseConnectionPool;
 // 没有用过的连接池
 private static HashMap nowUseConnectionPool;

 private static String dbDriver    = "odbc:jdbc:OdbcJdbcDriver";
 private static String dbUrl     = "dalong@XX";
 private static String userName    = "dalong";
 private static String userPassword   = "dalong";

 // 默认为100个连接池
 private static int  MAX_POOL    = 100;

 // singleTon 设计模式
 private ConnectionPool(String driver, String url, String name,
   String password, int max) throws ClassNotFoundException
 {
  Class.forName(driver);
  dbUrl = url;
  userName = name;
  userPassword = password;
  MAX_POOL = max;
 }

 public static ConnectionPool getConnManagerInstance(String poolName)
   throws ClassNotFoundException
 {
  ConnectionPool tempPool = (ConnectionPool) connectionPoolManager
    .get(poolName);
  if (tempPool == null)
  {
   tempPool = new ConnectionPool(dbDriver, dbUrl, userName,
     userPassword, MAX_POOL);
   connectionPoolManager.put(poolName, tempPool);
   return tempPool;
  }
  else
   return tempPool;
 }

 // 通过连接池获得真正的链接
 public static Connection getConnection() throws java.sql.SQLException
 {
  Connection conn = null;
  synchronized (noUseConnectionPool)
  {
   if (noUseConnectionPool.size() > 0)
   {
    conn = (Connection) noUseConnectionPool.firstElement();
    noUseConnectionPool.remove(conn);
    return conn;
   }
  }
  // 如果数据库连接池没有链接了，自己创建一个
  if (conn == null)
  {
   conn = createConnection(dbDriver, dbUrl, userName, userPassword);
  }
  else if (conn.isClosed())
  {
   nowUseConnectionPool.remove(conn);
   conn = createConnection(dbDriver, dbUrl, userName, userPassword);
  }
  conn.setAutoCommit(false);
  nowUseConnectionPool.put(conn, conn);
  return conn;
 }

 // 如果连接池没有链接了，就需要产生一个链接
 private static Connection createConnection(String driver, String url,
   String user, String password) throws java.sql.SQLException
 {
  Connection conn = DriverManager.getConnection(url, user, password);
  return conn;
 }

 public static void releaseConnection(Connection conn, boolean isCommit)
   throws java.sql.SQLException
 {
  if (isCommit) conn.commit();
  else
   conn.rollback();
  nowUseConnectionPool.remove(conn);
  if (noUseConnectionPool.size() + nowUseConnectionPool.size() < MAX_POOL)
  {
   synchronized (noUseConnectionPool)
   {
    noUseConnectionPool.add(conn);
   }
  }
  else
  {
   conn.close();
  }
 }

 public static void main(String[] args)
 {
  // 测试模拟10个客户
  for (int i = 0; i < 10; i++)
  {
   try
   {
    // xxxx 一般为属性文件读取
    ConnectionPool pool = ConnectionPool
      .getConnManagerInstance("xxxx");
    Connection conn = pool.getConnection();

   }
   catch (SQLException ex1)
   {
    // 处理异常
   }
   catch (ClassNotFoundException ex)
   {
    // 处理异常
   }
  }
 }
}