基础Java类使用类装载器实现装载配置文件

package com.bird.dao;

import java.io.FileInputStream;
import java.io.InputStream;
import java.util.Properties;

import org.junit.Test;

/**
 * @use Java普通类实现装载配置文件
 * @author Bird
 *
 */
public class UserDao {
	
	@Test//无法实现动态修改后呈现，因为直接装载到内存中是不会随着磁盘的文件的更改而更改的
	public void update() throws Exception{
		InputStream in = UserDao.class.getClassLoader().getResourceAsStream("db.properties");//得到当前类装载器装载配置文件
		Properties pro = new Properties();
		pro.load(in);
		
		String url = pro.getProperty("url");
		String username = pro.getProperty("username");
		String password = pro.getProperty("password");
		
		System.out.println(url);
		System.out.println(username);
		System.out.println(password);
	}
	
	
	@Test//可以时时的获得更改后的数据
	public void test() throws Exception{
		String path = UserDao.class.getClassLoader().getResource("db.properties").getPath();
		FileInputStream in = new FileInputStream(path);
		Properties pro = new Properties();
		pro.load(in);
		String url = pro.getProperty("url");
		String username = pro.getProperty("username");
		String password = pro.getProperty("password");
		
		System.out.println(url);
		System.out.println(username);
		System.out.println(password);
	}
}