7.10. Allowing Users to Upload Files

Problem

You need to allow users to upload file content to a web application.

Solution

Create an ActionForm that uses the Struts FormFile object as a property as shown in Example 7-10.

Example 7-10. ActionForm with FormFile property

package com.oreilly.strutsckbk.ch04;

import org.apache.struts.action.ActionForm;
import org.apache.struts.upload.FormFile;

public class UploadForm extends ActionForm {
    private FormFile content;

    public FormFile getContent( ) {
        return content;
    }
    public void setContent(FormFile content) {
        this.content = content;
    }
}

Then use the html:file tag on the JSP page (upload_test.jsp) that contains the form as shown in Example 7-11. For file uploads, the enctype attribute of the html:form tag must be set to multipart/form-data and the method attribute set to POST.

Example 7-11. JSP for file upload

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib uri="http://jakarta.apache.org/struts/tags-html" prefix="html" %>
  <html>
<head>
  <title>Struts Cookbook - Chapter 4 : Upload Test</title>
</head>
<body>
  <html:form action="/ProcessUpload"
             method="POST"
            enctype="multipart/form-data"> 
    <html:file property="content"/>
    <html:submit/>
  </html:form>
</body>
</html>

Tip

The default value for the method attribute of the html:form tag is POST, so the attribute isn't required here. In this case, however, explicitly setting the value reduces the risk of the method type being changed by another developer.

When the form is processed, ...

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