使用Commons-Pool写的数据库连接池_Java教程

1.数据库链接的接口类：DatabaseConnection

package net.pingsoft.kelefa.pool;

import Java.sql.*;
import javax.sql.*;
import com.wish.JDBC.WConnection;
import org.apache.commons.pool.*;
import org.apache.commons.pool.impl.*;
/**
 * 数据库链接的接口类.直接调用静态方法getDBConnection()取得Connection对象.
 * 相关的参数由PoolConfigServlet类根据web.XML设置,所以web.xml需要注册PoolConfigServlet
 *
 * Copyright: Copyright (c) 2004
 * @author kelefa yang
 * @version 1.0
 * @see PoolConfigServlet
 */
public class DatabaseConnection
{
  /** 数据库的用户名 */
  public static String USER = "sa";
  /** 数据库的用密码 */
  public static String PASS = "yf1";
  /** 数据库的启动程序类名 */
  public static String DBDRIVER =
      "com.microsoft.jdbc.sqlserver.SQLServerDriver";
  /** 数据库的链接地址 */
  public static String DBURL =
   "jdbc:microsoft:sqlserver://192.9.200.23:1433;DatabaseName=FC";
  /** 是否使用jndi */
  public static boolean useJNDI = false;
  /** jndi的名字,useJNDI==false时无效 */
  public static String JNDI = "wishJndi";
  /**
   * 是否对数据库链接进行编码转换
   * @deprecated 没有进行测试,应该直接设置数据库或在链接url加上编码参数
   */
  public static boolean convertConnetion = false;
  /** 是否缓冲链接 */
  public static boolean POOL_CONNECTION = false;
  /**
   * 没有必要生成实例
   */

  private DatabaseConnection()
  {}

  /**
   * 根据相应参数取回实际的数据库链接.
   * 假如useJNDI为真,根据JNDI名字从数据源取链接;否则直接从jdbc取链接.
   * 假如convertConnetion为真,对链接再封装,实现编码的转换.
   * @throws Exception 当useJNDI==false,并且USER,PASS,DBDRIVER,DBURL其中一个为空时
   * 抛出"DatabaseConnection didn't init!!"异常
   * @return Connection 数据库链接,取不到时返回null
   */
  static Connection getConnection() throws Exception
  {
    Connection conn = null;
    if( !useJNDI )
    {
      if( ( USER == null )  ( PASS == null )  ( DBDRIVER == null ) 
          ( DBURL == null ) )
        throw new Exception( "DatabaseConnection didn't init!!" );
      Class.forName( DBDRIVER );
      conn = DriverManager.getConnection( DBURL, USER, PASS );
    }
    else
    {
      DataSource ds = ServiceLocator.getInstance().getDataSource( JNDI );
      conn = ds.getConnection();
    }
    if( convertConnetion && conn != null )
      return new WConnection( conn );
    else
      return conn;
  }

  /** 链接池工厂 */
  private static GenericObjectPoolFactory poolFactory =
      new GenericObjectPoolFactory( new ConnectionFactory() );
  /** 数据库链接池 */
  private static ObjectPool pool = poolFactory.createPool();


  /**
   * if POOL_CONNECTION is true, return the pooled connetion.
   * POOL_CONNECTION will be set in Class PoolConfigServlet when webapp start,
   * you can change the value in web.xml.
   *    * <init-param>
   *    <param-name>poolConnection</param-name>
   *    <param-value>true</param-value>
   * </init-param>
   * 
   * @throws Exception
   * @return Connection
   */
  public static Connection getDBConnection() throws Exception
  {
    if( POOL_CONNECTION )
    {
      Object obj = pool.borrowObject();
      if( null == obj )
        return null;
      PoolableConnection conn = ( PoolableConnection )obj;
      conn.setPool( pool );
      return conn;
    }
    else
      return getConnection();
  }
}

2. 数据库链接工厂类ConnectionFactory

package net.pingsoft.kelefa.pool;