本文實例講述了JSP使用自定義標簽防止表單重復提交的方法。分享給大家供大家參考。具體如下：
1. 編寫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 { // 獲得輸入框中的值 String token = requset.getParameter("tokenName"); // 獲得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");//為了保證session中的值不重復，所以移除 } else { response.getWriter().print("對不起不能重復提交"); } }}2. 編寫自定義標簽的類：
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 是域對象同樣也是工具類 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. 編寫×.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"> <!-- 定義版本 --> <tlib-version>1.0</tlib-version> <!-- 定義名字 --> <short-name>apsliyuan</short-name> <!-- 定義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中的代碼：
<%@ 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. 防止亂碼的攔截器：
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("攔截完成"); } 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>
希望本文所述對大家的JSP程序設計有所幫助。
新聞熱點
疑難解答
