pool.java

tbuy1.1.5是在netbeans环境下用JSF技术编写的一个论坛tbuy1.1.5是在netbeans环境下用JSF技术编写的一个论坛

/*
 * 作者: 胡李青
 * qq: 31703299
 * Copyright (c) 2007 huliqing
 * 主页 http://www.tbuy.biz/
 * 你可以免费使用该软件，未经许可请勿作用于任何商业目的
 */

package biz.tbuy.common.pool;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

/**
 * @version 1.0
 * @author huliqing
 * <p><b>qq：</b>31703299
 * <p><b>E-mail：</b><a href="mailto:[e-mail]">[e-mail]</a>
 * <p><b>Homepage：</b><a href="http://www.tbuy.biz/">http://www.tbuy.biz/</a>
 */
public class Pool {
    private List<ProxyConn> _conns;
    
    private String _driver;
    private String _url;
    private String _user;
    private String _password;
    
    private List<String> _errors;    // 创建连接池过程中出现的错误
    
    /**
     * @param driver
     * @param url
     * @param user
     * @param password
     */
    public Pool(String driver, String url, String user, String password) {
        _driver = driver;
        _url = url;
        _user = user;
        _password = password;
        _conns = new ArrayList<ProxyConn>(PoolManager.getInstance().getMin());
        checkAndCreate();
    }
    
    /**
     * @return ArrayList<ProxyConn>
     */
    public List<ProxyConn> getConns() {
        return _conns;
    }
    
    /**
     * 获取连接池创建过程中遇到的错误
     */
    public List<String> getErrors() {
        return _errors;
    }
    
    /** method ****************************************************************/
    /**
     * 从数据库连接池中取得一个空闲连接
     * @return proxyConn 
     */
    public synchronized ProxyConn getConnection() {
        ProxyConn proxyConn = null;
        if (_conns == null || _conns.isEmpty()){
            checkAndCreate();
        }
        for (ProxyConn pConn : _conns) {
            if (pConn != null && !pConn.isClosed()) {
                if (!pConn.isBusy()) {
                    pConn.setBusy(true);
                    proxyConn = pConn;
                    break;
                }
            } else {
                _conns.remove(pConn);
            }
        }
        if (proxyConn == null) {
            // 如果连接已经满，但未达到最大允许连接数，则创建新连接
            if (_conns.size() < PoolManager.getInstance().getMax()) {
                try {
                   proxyConn = new ProxyConn(createConn());
                   _conns.add(proxyConn);
                } catch (Exception e) {}  
            } else {// 如果请求达到最大值，则稍后重试
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException ie) {}
                if (!_conns.isEmpty()) {
                    proxyConn = getConnection();
                }
            }
        }
        return proxyConn;
    }
    
    /**
     * 彻底关闭数据库连接
     */
    public synchronized void close() {
        int n = 1;
        for (ProxyConn proxyConn : _conns) {
            try {
                proxyConn.realClose();
            } catch (Exception e) {
                System.out.println("the connection close by Error::" + n);
                n++;
            }
        }
    }
    
    /**
     * 显示该连接池的当前状态
     */
    public synchronized void state() {
        System.out.println("All Connection:" + _conns.size());
        int n = 1;
        for (ProxyConn proxyConn : _conns) {
            if (proxyConn == null) {
                System.out.println("NO." + n + ":null");
            } else {
                if (proxyConn.isBusy()) {
                    System.out.println("NO." + n + ":busy:" + proxyConn.getStateTime()/1000);
                } else {
                    System.out.println("NO." + n + ":free:" + proxyConn.getStateTime()/1000);
                }
            }
            n++;
        }
    }
    
    /**
     * 检查与创建连接，直到连接数达到连接池的最少限制数
     */
    public synchronized void checkAndCreate() {
        while (_conns.size() < PoolManager.getInstance().getMin()) {
            try {
                _conns.add(new ProxyConn(createConn()));
            } catch (Exception e) {
                return;
            }
        }
    }
    
    /**
     * 创建一个新的数据链接至连接池中。
     */
    public synchronized Connection createConn() 
            throws ClassNotFoundException, SQLException {
        Connection conn = null; 
        Class.forName(_driver);
        conn = DriverManager.getConnection(_url, _user, _password);
        // System.out.println("创建新连接.........................");
        return conn;
    }
    
    /**
     * 释放指定的代理连接,并不真正关闭该连接
     */
    private void release(ProxyConn conn) {
        conn.close();
    }
}