session防止表单重复提交

来源：互联网发布：js arraybuffer 编辑：程序博客网时间：2024/05/14 17:27
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html>   <head>     <title>RepeateForm.html</title>     <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">     <meta http-equiv="description" content="this is my page">     <meta http-equiv="content-type" content="text/html; charset=UTF-8">          <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->     <script type="text/javascript">     var iscommitted = false;     function checkPost(){       if(!iscommitted){           document.getElementById("sub").disabled =turn;            iscimmitted = turn;           return trun;             }else{         //  alert("不能重复提交表单！");           return false;               }     }     </script>   </head>      <body>     <form action="/BookHistory/serlevt/RepeateFormServlet" method="poss" onsubmit="return checkPost()">     用户名:<input type="text" name="username" /><br>       <input type="submit" value="提交" id="sub"/>     </form>      </body> </html> package com.hbsi.servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class FormDealServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { /* String client_token = request.getParameter("token"); if(client_token==null){ return false;*/ boolean b = isTokenValidate(request); if(!b){ System.out.print("请不要重复提交"); return; } request.getSession().removeAttribute("token"); System.out.print("项数据库注册用户信息。。。"); }     private boolean isTokenValidate(HttpServletRequest request){     String client_token = request.getParameter("token"); if(client_token==null){ return false;          } String server_token=(String) request.getSession().getAttribute("token"); if(server_token==null){ return false; } if(!client_token.equals(server_token)){ return false; } return true;   } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } } package com.hbsi.servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class ForeGenerateServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/heml;charset=UTF-8"); PrintWriter out = response.getWriter(); //产生表单号 TokenProcessor tp = TokenProcessor.getInstance(); String token= tp.generateToken(); request.getSession().setAttribute("token", token);  out.print("<form action='/BookHistory/servlet/FormDealServlet' method='post'/>"); out.print("<input type='hidden' name='token' value='"+token+"'/>"); out.print("用户名：<input type='text' name='username'/>"); out.print("<input type='submit' value='提交'/>"); out.print("</form>"); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } } package com.hbsi.servlet; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.Random; import sun.misc.BASE64Encoder; public class TokenProcessor { private TokenProcessor(){ } private static final TokenProcessor instance=new TokenProcessor(); public static TokenProcessor getInstance(){ return instance; } public String generateToken(){ int i= new Random().nextInt(); String token= System.currentTimeMillis()+i+""; try { MessageDigest md=MessageDigest.getInstance("md5");          byte[]md5 = md.digest(token.getBytes());          //base64编码 BASE64Encoder encoder = new BASE64Encoder();  encoder.encode(md5); //return new String(md5);            } catch (NoSuchAlgorithmException e) { // TODO Auto-generated catch block //e.printStackTrace(); throw new RuntimeException(e); } return null; } } package com.hbsi.servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class RepeateFormServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter(); String username = request.getParameter("username"); try { Thread.sleep(5*1000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } out.print("以处理你的信息"); System.out.println("向数据库注册信息……"); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request,response); } }