作业--->利用session防止表单重复提交

来源：互联网发布：考研软件编辑：程序博客网时间：2024/05/22 15:04

<!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">


<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);

}

}