JSP使用自定义标签防止表单重复提交的方法

2024-09-05 00:22:17

字体：大中小

来源：转载

供稿：网友

这篇文章主要介绍了JSP使用自定义标签防止表单重复提交的方法,以实例形式较为详细的分析了JSP基于自定义标签防止表单重复提交的具体步骤与实现方法,具有一定参考借鉴价值,需要的朋友可以参考下

本文实例讲述了JSP使用自定义标签防止表单重复提交的方法。分享给大家供大家参考。具体如下：

1. 编写servelt：

package cn.itcast.apsliyuan.web.servlet;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class LoginServet extends HttpServlet {

/**

* 反序列化

*/

private static final long serialVersionUID = 4960707156159691747L;

@Override

public void doPost(HttpServletRequest requset,

HttpServletResponse response) throws ServletException, IOException {

// 获得输入框中的值

String token = requset.getParameter("tokenName");

// 获得session中的值

String sessionToken = (String) requset.getSession().getAttribute(

"token");

if (token.equals(sessionToken)) {

response.getWriter().print("保存成功");

requset.getSession().removeAttribute("token");//为了保证session中的值不重复，所以移除

} else {

response.getWriter().print("对不起不能重复提交");

}

}

}

2. 编写自定义标签的类：

package cn.itcast.apsliyuan.tag;

import java.io.IOException;

import java.util.UUID;

import javax.servlet.jsp.JspException;

import javax.servlet.jsp.tagext.TagSupport;

public class LoginTokenTag extends TagSupport{

/**

* 凡序列化

*/

private static final long serialVersionUID = -1815168785364991254L;

@Override

public int doStartTag() throws JspException {

// TODO Auto-generated method stub

//得到uuid

String uuid=UUID.randomUUID().toString().replace("-","");

//得到session,pageContext 是域对象同样也是工具类

pageContext.getSession().setAttribute("token",uuid);

String html="<input type='text' name='tokenName' readonly='readonly' value="+uuid+">";

try {

pageContext.getOut().print(html);

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return EVAL_BODY_INCLUDE;

}

}

3. 编写×.tld文件：

<?xml version="1.0" encoding="UTF-8" ?>

<taglib 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-jsptaglibrary_2_1.xsd"

version="2.1">



<tlib-version>1.0</tlib-version>



<short-name>apsliyuan</short-name>



<uri>http://my.oschina.net/aps</uri>

<tag>

<name>loginTokenTag</name>

<tag-class>cn.itcast.apsliyuan.tag.LoginTokenTag</tag-class>

<body-content>JSP</body-content>

</tag>

</taglib>

4. jsp中的代码：

<%@ page language="java" contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%>

<%@taglib uri="http://my.oschina.net/aps" prefix="aps" %>

<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>index.jsp</title>

</head>

<body>

<form action="${pageContext.request.contextPath}/server/Login" method="post">

<aps:loginTokenTag/>

<input type="submit" value="Login"/>

</form>

</body>

</html>

5. 防止乱码的拦截器：

package cn.itcast.apsliyuan.filter;

import java.io.IOException;

import javax.servlet.Filter;

import javax.servlet.FilterChain;

import javax.servlet.FilterConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletRequest;

import javax.servlet.ServletResponse;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class UncodeFilter implements Filter {

public void init(FilterConfig filterConfig) throws ServletException {

// TODO Auto-generated method stub

System.out.println("拦截完成");

}

public void doFilter(ServletRequest req, ServletResponse res,

FilterChain chain) throws IOException, ServletException {

HttpServletRequest request=(HttpServletRequest) req;

HttpServletResponse response=(HttpServletResponse) res;

request.setCharacterEncoding("UTF-8");

response.setContentType("text/html;charset=UTF-8");

chain.doFilter(request, response);

}

public void destroy() {

// TODO Auto-generated method stub

}

}

6. web.xml中的配置：

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"

id="WebApp_ID" version="2.5">

<display-name>Tag</display-name>

<welcome-file-list>

<welcome-file>index.html</welcome-file>

<welcome-file>index.htm</welcome-file>

<welcome-file>index.jsp</welcome-file>

<welcome-file>default.html</welcome-file>

<welcome-file>default.htm</welcome-file>

<welcome-file>default.jsp</welcome-file>

</welcome-file-list>

<servlet>

<servlet-name>loginServlet</servlet-name>

<servlet-class>cn.itcast.apsliyuan.web.servlet.LoginServet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>loginServlet</servlet-name>

<url-pattern>/server/Login</url-pattern>

</servlet-mapping>

<filter>

<filter-name>UncodeFilter</filter-name>

<filter-class>cn.itcast.apsliyuan.filter.UncodeFilter</filter-class>

</filter>

<filter-mapping>

<filter-name>UncodeFilter</filter-name>

<url-pattern>/*</url-pattern>

</filter-mapping>

</web-app>