电子工业出版社《Java Web程序设计》练习2.E.2-CFANZ编程社区

习题分析

题目描述

在这里插入图片描述

login.jsp

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
 <%@taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>登录</title>
<script type="text/javascript">
	function LoginSubmit()
	{
		var id= document.loginpage.id.value;
		var pwd=document.loginpage.pwd.value;
		if(id==null||id=="")
			{
				alert("请填写用户名！");
			}
		else if(pwd==null||pwd=="")
			{
				alert("请填写密码！");
			}
		else
			document.loginpage.submit();
	}
</script>
</head>
<body>
	<center>
		<form action="CheckServlet" method="post" name="loginpage">
			PersonalID:<input type="text" name="id">
			<br>
			password:<input type="password" name="pwd">
			<br>
			<input type="button" value="一键提交" onclick="LoginSubmit()">
		</form>
	</center>
</body>
</html>

CheckServlet.java

package com.servelt;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.RequestDispatcher;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class CheckServlet
 */
@WebServlet("/CheckServlet")
public class CheckServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public CheckServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		System.out.println("后台：提交信息确认");
		request.setCharacterEncoding("GBK");
		response.setContentType("text/html;charset=GBK");
		PrintWriter out=response.getWriter();
		String id=request.getParameter("id");
		String pwd=request.getParameter("pwd");
		System.out.println("后台:用户名"+id+"  密码"+pwd);
		if(check(id, pwd))//如果密码账户正确
		{
			//Session处理
			HttpSession session=request.getSession();
			session.setAttribute("id", id);
			session.setAttribute("pwd", pwd);
			//请求转移
			RequestDispatcher rd=request.getRequestDispatcher("/MainServlet");
			rd.forward(request, response);
		}
		else
		{
			out.println("<html>");
			out.println("<head><title>检查界面</title></head>");
			out.println("<body><center>");
			out.println("密码或账号有误！");
			out.println("<a href='login.jsp'>重新登录</a>");
			out.println("</center></body></html>");
		}
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}
	private boolean check(String id, String pwd)
	{
		boolean flag=false;//默认为无法登录
		if(id.equals("haier")&&pwd.equals("soft"))
		{
			flag=true;
		}
		return flag;
	}

}

MainServlet.java

package com.servelt;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class MainServlet
 */
@WebServlet("/MainServlet")
public class MainServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public MainServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		request.setCharacterEncoding("GBK");
		response.setContentType("text/html;charset=GBK");
		PrintWriter out=response.getWriter();
		System.out.println("后台：请求转移测试");
		String id=request.getParameter("id");
		String pwd=request.getParameter("pwd");
		System.out.println("后台:用户名"+id+"  密码"+pwd);
		HttpSession session=request.getSession();
		String sessionId=session.getId();
		long sessionSTA=session.getCreationTime();
		int sessionMax=session.getMaxInactiveInterval();
		out.println("<html>");
		out.println("<head><title>主界面</title></head>");
		out.println("<body><center>");
		out.println("SessionID:"+sessionId+"<br>");
		out.println("Session创建时间:"+sessionSTA+"<br>");
		out.println("Session创建时效:"+sessionMax+"<br>");
		//建立一个“注销”的超链接
		out.println("<a href='DestroySession'>注销</a>");
		out.println("</center></body></html>");
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

DestroySession.java

package com.servelt;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class DestroySession
 */
@WebServlet("/DestroySession")
public class DestroySession extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public DestroySession() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		System.out.println("后台：测试超链接效果");
		request.setCharacterEncoding("GBK");
		response.setContentType("text/html;charset=GBK");
		PrintWriter out=response.getWriter();
		HttpSession session=request.getSession();
		String id=(String)session.getAttribute("id");
		String pwd=(String)session.getAttribute("pwd");
		System.out.println("后台:尝试Sessions是否奏效");
		System.out.println("后台:用户名"+id+"  密码"+pwd);
		session.invalidate();
		out.println("<html>");
		out.println("<head><title>注销界面</title></head>");
		out.println("<body><center>");
		out.println("成功注销SessionID");
		out.println("</center></body></html>");
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}