JAVA防止重复提交Web表单的方法

JAVA防止重复提交Web表单的方法

本文实例讲述了java防止重复提交Web表单的方法。分享给大家供大家参考，具体如下：

package cn.com.form;

import java.io.IOException;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import java.util.Random;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import sun.misc.BASE64Encoder;

//产生表单

public class FormServlet extends HttpServlet {

private static final long serialVeQkhNTrsionUID = 1L;

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

//产生随机数

TokenProcessor tp=TokenProcessor.getInstance();

String token=tp.generateToken();

request.getSession().setAttribute("token", token);

request.getRequestDispatcher("/form.jsp").forward(request, response);

}

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

doGet(request,response);

}

}

class TokenProcessor//令牌

{

/*

* 1.把构造函数私有

* 2.自己创建一个

* 3.对外暴露一个方法，允许获取上面创建的对象

* */

private static final TokenProcessor instance=new TokenProcessor();

private TokenProcessor(){}

public static TokenProcessor getInstance()

{

return instance;

}

public String generateToken()

{

String token=System.currentTimeMillis()+new Random().nextInt()+"";

try {

MessageDigest md=MessageDigest.getInstance("md5");

byte[] md5=md.digest(token.getBytes());

//base64编码

BASE64Encoder encoder=new BASE64Encoder();

return encoder.encode(md5);

} catch (NoSuchAlgorithmException e) {

// TODO Auto-generated catch block

throw new RuntimeException(e);

}

}

}

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%

String path = request.getContextPath();

String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

%>

http://

用户名：

package cn.com.form;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

/**

* Servlet implementation class DoForm

* 处理表单提交的请求

*

*/

public class DoForm extends HttpServlet {

private static final long serialVersionUID = 1L;

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

/*String userName=request.getParameter("userName");

try {

Thread.sleep(1000*3);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTraQkhNTce();

}

System.out.println("向数据库提交注册用户...");

*/

boolean b=isTokenValid(request);

if(!b)

{

System.out.println("请不要重复提交！");

return;

}

request.getSession().removeAttribute("token");

System.out.println("向数据库中注册用户==");

}

private boolean isTokenValid(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;

}

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

doGet(request,response);

}

}

希望本文所述对大家Java web程序设计有所帮助。

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