February 2005
Intermediate to advanced
528 pages
12h 53m
English
Content preview from Jakarta Struts CookbookBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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7.9. Preventing Double Form Submissions
Problem
You need to stop users from inadvertently submitting a form twice.
Solution
Use the
Struts token facility to
reject a duplicate request. First, as shown in Example 7-6, save a token in the HTTP request in the
Action which precedes the JSP containing the form.
Example 7-6. Action that saves token
package com.oreilly.strutsckbk.ch06;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
public class SaveTokenAction extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
// save a token
saveToken(request);
// load the data to view
BusinessService.loadData( );
return mapping.findForward("success");
}
}You don't have to make any changes to the JSP that
displays the form as long as you create the form using the
html:form tag (as shown in Example 7-7).
Example 7-7. JSP page for token handling
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <%@ taglib uri="http://struts.apache.org/tags-html" prefix="html" %> <html> <head> <title>Struts Cookbook - Chapter 7 : Token Test</title> </head> <body bgcolor="white"> <h2>Token Test</h2> <html:errors/> <html:form action="/SaveData"> <html:text property="name"/> <html:submit/> ...
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