jdbcdbsimp.java.svn-base

tapestry json 实现从数据库读取数据生成树

package com.datasource;

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


public class JDBCDBSImp implements DBSource {

	private String url;

	private String user;

	private String passwd;

	private String driverName;
	
	private int iPoolSize;
	
	private ArrayList<Connection> lstPool = new ArrayList<Connection>();

	public JDBCDBSImp(String url, String user, String passwd, String driverName, int poolSize) {
		this.url = url;
		this.user = user;
		this.passwd = passwd;
		this.driverName = driverName;
		this.iPoolSize	= poolSize;
		this.initPool();
	}
	
	public void initPool(){
		Connection conn = null;
		int j = 0; 				//������l�Ӹ���
		for(int i=0;i<iPoolSize;i++){
			conn = this.addConnection(this.url, this.user, this.passwd, this.driverName);
			if(conn!=null){
				lstPool.add(conn);
				j++;
			}
			conn = null;
		}
		if(j==0){
			System.out.println("连接池初始化失败,请检查配置");
			//可在此处抛出异常
		}
		else{
			System.out.println("初始化连接池:"+j+"个连接创建");
		}
	}

/**
 * 加载数据库库驱动，并获得一个连接
 * @param url数据库URL jdbc:oracle:thin:@192.168.1.109:1521:ORCL
 * @param user数据库的用户名
 * @param passwd数据库的密码
 * @param driverName数据库驱动程序
 * @return
 */
	private Connection addConnection(String url, String user, String passwd,
			String driverName) {
		Connection conn = null;
		try {
			
			Class.forName(driverName);
			conn = DriverManager.getConnection(url, user, passwd);
		} catch (ClassNotFoundException e) {
			System.out.println("=========δ������̳���=========");
			e.printStackTrace();
		} catch (SQLException e) {
			System.out.println("=========δ�õ�l�ӣ�=========");
			e.printStackTrace();
		} catch (Exception e) {
			System.out.println("=========δ֪�쳣(JDBCDSImp)=========");
			e.printStackTrace();
		}
		return conn;
	}
	
	/**
	 * 
	 * 
	 * 从池中拿出连接
	 * 
	 */
	public synchronized Connection getConnection() {
		Connection conn=null;
		if(lstPool.size()==0){
			conn = this.addConnection(this.url, this.user, this.passwd, this.driverName);
			//如果获取失败,则继续两次��
			if(conn == null){
				for(int i=0;i<2;i++){
					conn = this.addConnection(this.url, this.user, this.passwd, this.driverName);
					if(conn!=null) break;
				}
			}
		}
		else{
			conn = lstPool.get(0);
			lstPool.remove(0);
		}
		return conn;
	}
	
	/**
	 * 将有效连接放回到连接池,便于后续使用
	 */
	public synchronized void putConnection(Connection conn){
		if(conn == null) return;
		try{
			if(conn.isClosed()) return;
		}catch(Exception e){
			return;
		}
		lstPool.add(conn);
	}
}