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">
<!-- 定义版本 -->
<tlib-version>1.0</tlib-version>
<!-- 定义名字 -->
<short-name>apsliyuan</short-name>
<!-- 定义uri -->
<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>
希望本文所述对大家的jsp程序设计有所帮助。
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