session应用----登录验证小案例
1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 2 <% 3 String path = request.getContextPath(); 4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 5 %> 6 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 7 <html> 8 <head> 9 <base href="<%=basePath%>"> 10 <title>My JSP 'index.jsp' starting page</title> 11 <meta http-equiv="pragma" content="no-cache"> 12 <meta http-equiv="cache-control" content="no-cache"> 13 <meta http-equiv="expires" content="0"> 14 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 15 <meta http-equiv="description" content="This is my page"> 16 </head> 17 <script type="text/javascript"> 18 function func() { 19 document.getElementById("ima1").src="VerifyCodeServlet?a="+new Date().getTime(); 20 } 21 </script> 22 <body> 23 <% 24 String msg=""; 25 String s=(String)request.getAttribute("msg"); 26 if(s!=null) msg=s; 27 %> 28 <h1>登录</h1> 29 <font color="red"><%=msg %></font> 30 <form action="AServlet" method="post"> 31 用户名：<input type="text" name="uname"><br> 32 验证码：<input type="text" name="verifyCode" size="4"> 33 <img id="ima1" src="VerifyCodeServlet"/> 34 <a href="javascript:func();">看不清，换一张</a><br> 35 <input type="submit" value="提交"> 36 </form> 37 </body> 38 </html>
1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 2 <% 3 String path = request.getContextPath(); 4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 5 %> 6 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 7 <html> 8 <head> 9 <base href="<%=basePath%>"> 10 <meta http-equiv="pragma" content="no-cache"> 11 <meta http-equiv="cache-control" content="no-cache"> 12 <meta http-equiv="expires" content="0"> 13 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 14 <meta http-equiv="description" content="This is my page"> 15 </head> 16 <% 17 String uname=(String)request.getSession().getAttribute("uname"); 18 if(uname==null) 19 { 20 request.setAttribute("msg", "请先登录！"); 21 response.sendRedirect("index.jsp"); 22 } 23 %> 24 <body> 25 欢迎<%=uname %> 26 </body> 27 </html>
1 package cn.yzu; 2 import java.awt.image.BufferedImage; 3 import java.io.IOException; 4 import javax.servlet.ServletException; 5 import javax.servlet.http.HttpServlet; 6 import javax.servlet.http.HttpServletRequest; 7 import javax.servlet.http.HttpServletResponse; 8 9 public class VerifyCodeServlet extends HttpServlet { 10 public void doGet(HttpServletRequest request, HttpServletResponse response) 11 throws ServletException, IOException { 12 VerifyCode verifyCode = new VerifyCode(); 13 BufferedImage bi = verifyCode.getImage(); 14 request.getSession().setAttribute("vc", verifyCode.getText()); 15 verifyCode.output(bi,response.getOutputStream()); 16 } 17 18 }
1 package cn.yzu; 2 import java.io.IOException; 3 import javax.servlet.ServletException; 4 import javax.servlet.http.HttpServlet; 5 import javax.servlet.http.HttpServletRequest; 6 import javax.servlet.http.HttpServletResponse; 7 public class AServlet extends HttpServlet { 8 public void doPost(HttpServletRequest request, HttpServletResponse response) 9 throws ServletException, IOException { 10 String uname=request.getParameter("uname"); 11 String verifyCode=request.getParameter("verifyCode"); 12 if(uname.equals("fmy")&&verifyCode.equalsIgnoreCase((String) request.getSession().getAttribute("vc"))) 13 { 14 request.getSession().setAttribute("uname", uname); 15 response.sendRedirect("suc.jsp"); 16 } 17 else 18 { 19 request.setAttribute("msg", "用户名或者验证码错误！"); 20 request.getRequestDispatcher("index.jsp").forward(request, response); 21 } 22 } 23 }
运行界面：
注：verifyCode类见博客：http://www.cnblogs.com/fengmingyue/p/5987814.html
