servicelistener.java

一个用纯JAVA语言做的一个拥护登录系统,用道到了HashMap ,HashList,很适合初学者.

package leng.servlet;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextListener;
import javax.servlet.ServletContextEvent;

import java.util.ArrayList;
import java.util.HashMap;

import leng.entity.User;

//创建侦听application的侦听类

public class ServiceListener implements ServletContextListener
{
	//往方法中传递侦听application所产生的事件
	public void contextInitialized(ServletContextEvent sce) {
		
		ServletContext application = sce.getServletContext();//通过application事件返回application对象
		ArrayList userList = new ArrayList();//创建一个ArrayList容器用于存储user对象
		
		//创建用户，存入list
		userList.add(new User("leng", "123"));
		userList.add(new User("hele", "hele"));
		userList.add(new User("liuyang", "liuyang"));
		userList.add(new User("xiaheng", "xiaheng"));

		application.setAttribute("userList", userList);//将学生列表存入application
		HashMap stuMap = new HashMap();//创建map用于存放student对象
		application.setAttribute("stuMap", stuMap);//将学生map存入application
//		System.out.println("***listener***");
	}

	public void contextDestroyed(ServletContextEvent sce) {
	
	}
}