起风网<!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” οnsubmit=”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);
}
}
转载于:https://www.cnblogs.com/zgl521/archive/2012/11/06/3057778.html
原文链接：https://blog.csdn.net/weixin_30342827/article/details/97523872
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