urlclassloadertest.java

疯狂Java讲义_源码(含Java设计模式CHM

import java.net.*;
import java.sql.*;
import java.util.*;

/**
 * Description:
 * <br/>Copyright (C), 2008-2010, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee [e-mail]
 * @version  1.0
 */
public class URLClassLoaderTest
{
	private static Connection conn;
	//定义一个获取数据库连接方法
	public static Connection getConn(String url , 
		String user , String pass)throws Exception
	{
		if (conn == null)
		{
			//创建一个URL数组
			URL[] urls = {new URL("file:mysql-connector-java-3.1.10-bin.jar")};
			//以默认的ClassLoader作为父ClassLoader，创建URLClassLoader
			URLClassLoader myClassLoader = new URLClassLoader(urls);
			//加载MySQL的JDBC驱动，并创建默认实例
			Driver driver = (Driver)myClassLoader.
				loadClass("com.mysql.jdbc.Driver").newInstance();
			//创建一个设置JDBC连接属性的Properties对象
			Properties props = new Properties();
			//至少需要为该对象传入user和password两个属性
			props.setProperty("user" , user);
			props.setProperty("password" , pass);
			//调用Driver对象的connect方法来取得数据库连接
			conn = driver.connect("jdbc:mysql://localhost:3306/mysql" , props);
		}
		return conn;
	}
	public static void main(String[] args)throws Exception
	{
		System.out.println(getConn(
			"jdbc:mysql///mysql"
			, "root" , "32147"));
	}
}