token防止表单重复提交详解编程语言

出现表单重复提交的三种情况：

一、服务器响应缓慢，用户多次点击提交按钮。

二、提交成功后刷新页面。

三、提交成功后返回表单页面再次点击提交。

package com.jalja.token; 
import java.io.IOException; 
import java.io.PrintWriter; 
import java.util.UUID; 
 
import javax.servlet.ServletException; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
public class UserServlet  extends HttpServlet{ 
    public void doGet(HttpServletRequest request, HttpServletResponse response) 
            throws ServletException, IOException { 
        doPost(request, response); 
    } 
    public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException { 
        request.setCharacterEncoding("utf-8"); 
        response.setContentType("text/html;charset=utf-8"); 
        String contextPath=request.getContextPath(); 
        String requestURI=request.getRequestURI(); 
        String path=requestURI.substring(contextPath.length()+1, requestURI.length()); 
        String token=""; 
        if(path.equals("index.do")){ 
            token = UUID.randomUUID().toString();//创建令牌 
            System.out.println("在FormServlet中生成的token："+token); 
            request.getSession().setAttribute("token", token);  //在服务器使用session保存token(令牌) 
            request.getRequestDispatcher("/index.jsp").forward(request, response);//跳转到form.jsp页面 
        } 
        if(path.equals("token.do")){ 
            String name=request.getParameter("username"); 
            String tokenValue=request.getParameter("tokenValue");//获取客户端的Token 
            System.out.println("获取客户端的token："+tokenValue); 
            String server_token = (String) request.getSession().getAttribute("token");//获取服务器端的token 
            if(tokenValue!=null && server_token!=null && server_token.equals(tokenValue)){ 
                System.out.println("处理请求; 获得name==》"+name); 
                try { 
                    Thread.sleep(3*1000);//模拟网络延迟 
                } catch (InterruptedException e) { 
                    e.printStackTrace(); 
                } 
            }else{ 
                System.out.println("不处理"); 
 
            } 
            request.getSession().removeAttribute("token");//每次处理玩请求都要移除掉token 
        } 
    } 
     
}

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 
<!DOCTYPE HTML> 
<html> 
  <head> 
    <title>Form表单</title> 
  </head> 
  <body> 
      <h2>防止表单重复提交</h2> 
      <form action="${pageContext.request.contextPath}/token.do"  method="post"> 
         <input type="hidden" value="${token}" name="tokenValue"/> 
                 用户名：<input type="text" name="username"/> 
        <input type="submit" value="提交" id="submit"/> 
    </form> 
  </body> 
</html>

<?xml version="1.0" encoding="UTF-8"?>   
<web-app version="2.5"    
    xmlns="http://java.sun.com/xml/ns/javaee"    
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee    
    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">  
    <servlet>   
        <servlet-name>token</servlet-name>   
        <servlet-class>com.jalja.token.UserServlet</servlet-class>   
        <load-on-startup>1</load-on-startup>   
    </servlet>   
    <servlet-mapping>   
        <servlet-name>token</servlet-name>   
        <url-pattern>*.do</url-pattern>   
    </servlet-mapping>    
</web-app>

原创文章，作者：奋斗，如若转载，请注明出处：https://blog.ytso.com/16035.html

token防止表单重复提交详解编程语言

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