简单登录页面以及实现保存用户的信息

AServlet的代码：

public class AServlet extends HttpServlet {

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		response.setContentType("text/html;charset=utf-8");
		String userString=request.getParameter("username");
		String userpassString =request.getParameter("password");
		//System.out.println(userString+userpassString);为看输入的登录名和密码
	if("admin".equals(userString)&&"12345".equals(userpassString)){
//		if(!"admin".equalsIgnoreCase(userString)){
			/**
			 * 使用Cookie来保存用户名,发送给客户端浏览器
			 * 当再次打开login.jsp会读取Cookie把它显示到用户名文本输入框
			 * 
			 */
		Cookie cookie1=new Cookie("userString", userString);//创建cookie
		cookie1.setMaxAge(60*60*24);//设置cookie的生存时间一天
		response.addCookie(cookie1);//保存cookie
			/**
			 * 重定向必须要加项目名
			 * 请求转发可以不加项目名你
			 * 请求成功之后跳转到success1.jsp
			 */
		HttpSession session=request.getSession();//获取session
		session.setAttribute("userString", userString);//向session域中保存用户名
		response.sendRedirect("/Demo11Session/loginpage/success1.jsp");
		}else {
			//response.sendRedirect("/Demo11Session/loginpage/error.jsp");
			/**
			 * 如果错误则进行信息提示及转发到登陆页面
			 * 同时保存错误的的信息到request域中
			 */
			request.setAttribute("msg", "登录错误");
			RequestDispatcher rp=request.getRequestDispatcher("/loginpage/login.jsp");//重定向到登录页面被
			rp.forward(request, response);
		
		}
		
	}

}

VerifyServlet的代码：

login.jsp页面代码：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'login.jsp' starting page</title>
    
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
   <h1>欢迎登录！</h1>
   <%/*读取名为userString的cookie*/
   String username="";
   Cookie[] csCookie=request.getCookies();//获取请求中所有cookie
   if(csCookie!=null){//如果存在cookie
   for(Cookie c:csCookie){//循环遍历所有的cookie
   		if("username".equals(c.getName())){//在所有cookie中寻找名为username
   		username=c.getValue();//获取这个cookie的值给username
   		}
   }
   } %>
  <font color="red"><b>
   <%
   String msg=(String)request.getAttribute("msg"); //获取错误信息
   if(msg!=null){
   out.print(msg);
   }
   else{%>
   <%
   out.print("");
   }
   %>
   </b>
   </font>
   <form action="/Demo11Session/AServlet" method="post">
   <%--把用户名保存到用户名文本框 --%>
   用户名:<input type="text" name="username" value="<%=username%>"/><br/>
   密&nbsp;码：<input type="password" name="password"/><br/>
   验证码：<input type="text" name="verifyCode"/>
   <img alt="验证码" src="/Demo11Session/VerifyServlet"/><!-- img标签的地址要项目名 -->
   <input type="submit" value="提交"/>
   </form>
  </body>
</html>

登录结果的代码：

package com.myservlet.shape;

import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class VerifyServlet extends HttpServlet {
	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		response.setContentType("text/html;charset=uft-8");
		/**
		 * 生成图片
		 * 保存图片的文本到session文件中
		 * 把图片响应给客服端
		 */
		VerifyCode vCode=new VerifyCode();//此处引用了生成图片验证码的VerifyCode.java
		BufferedImage image=vCode.getImage();
		request.getSession().setAttribute("session_vcode", vCode.getText());//将图片上的文本获取到session域中
		VerifyCode.output(image, response.getOutputStream());
		
	}

}

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'success1.jsp' starting page</title>
    
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
    <h1>登录1</h1>
    <% String username=(String) session.getAttribute("userString");
    if(username==null){
    /*向request域中保存错误信息，转发到登陆页面login.jsp*/
    request.setAttribute("msg", "您还没有登录");
    request.getRequestDispatcher("/loginpage/login.jsp").forward(request, response);
    return;/*不执行后面代码，你需要跳出它,可以直接用return而不能加任何量在后面了*/
    }%>
    热烈欢迎<font><b><%out.print(session.getAttribute("userString")); %></b></font>
    感谢您的一路相伴
  </body>
</html>

测试结果

过期时间为一天

简单登录页面以及实现保存用户的信息

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