1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <%@taglib uri="/struts-tags" prefix="s"%>
 4 <!DOCTYPE html>
 5 <html>
 6     <head>
 7         <meta charset="UTF-8">
 8         <title>struts2的一个例子</title>
 9     </head>
10     <body>
11         <form action="downloadFile.action" method="post" enctype="multipart/form-data">
12             文件名：<input type="text" name="fileName" value="CSS"/>.jpg<br/>
13             <input type="submit" value="下载文件">
14         </form>
15         
16     </body>
17 </html>
index.jsp代码 
 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <!DOCTYPE struts PUBLIC
 3     "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
 4     "http://struts.apache.org/dtds/struts-2.3.dtd">
 5 <struts>
 6     <constant name="struts.devMode" value="true"/>
 7     <package name="hello" extends="struts-default" namespace="/">
 8         <action name="downloadFile" class="com.xiaostudy.web.DownloadFile" method="downloadFile">
 9             <result name="success" type="stream">
10                 <param name="inputName">fileInputStream</param>
11                 <param name="contentDisposition">attachment;filename="${fileName}.jpg"</param>
12                 <param name="contentType">application/octet-stream</param>
13             </result>
14         </action>
15     </package>
16 </struts>
struts.xml代码 
 1 package com.xiaostudy.web;
 2 
 3 import java.io.File;
 4 import java.io.FileInputStream;
 5 import java.io.FileNotFoundException;
 6 import java.io.IOException;
 7 import java.io.InputStream;
 8 import java.io.UnsupportedEncodingException;
 9 
10 import org.apache.struts2.ServletActionContext;
11 
12 import com.opensymphony.xwork2.ActionSupport;
13 
14 public class DownloadFile extends ActionSupport {
15     
16     public InputStream fileInputStream;
17     public String fileName;
18     
19     public String downloadFile() throws IOException {
20         
21         String path = ServletActionContext.getServletContext().getRealPath("/WEB-INF/files/CSS.jpg");
22         fileInputStream = new FileInputStream(new File(path));
23         this.fileName = new String(fileName.getBytes(), "ISO8859-1");
24         
25         return SUCCESS;
26     }
27     
28     public String getFileName() {
29         return fileName;
30     }
31     public void setFileName(String fileName) {
32         this.fileName = fileName;
33     }
34     public InputStream getFileInputStream() {
35         return fileInputStream;
36     }
37     public void setFileInputStream(InputStream fileInputStream) {
38         this.fileInputStream = fileInputStream;
39     }
40 
41 
42 }
action动作类DownloadFile