public class DownLoadAction extends ActionSupport { 
/** 
* 
*/ 
private static final long serialVersionUID = 5879762231742395104L; 
private String fileName;//用户请求的文件名 
private String inputPath;//下载资源的路径(在struts配置文件中设置) 
public void setInputPath(String inputPath) { 
this.inputPath = inputPath; 
} 
public String getInputPath() { 
return inputPath; 
} 
public void setFileName(String fileName) { 
this.fileName = fileName; 
} 
public String getFileName() { 
return fileName; 
} 
public String downloadFile() throws Exception { 
ServletContext context = ServletActionContext.getServletContext(); 
String downloadDir = context.getRealPath("/upload"); 
String downloadFile = context.getRealPath(inputPath); 
//防止用户请求不安全的资源 
if(!downloadFile.startsWith(downloadDir)) { 
return null; 
} 
return "download_success"; 
} 
/* 
* 获取输入流资源 
*/ 
public InputStream getInputStream() throws Exception { 
String path = inputPath + File.separatorChar + new String(fileName.getBytes("ISO-8859-1"), "UTF-8"); 
return ServletActionContext.getServletContext().getResourceAsStream(path); 
} 
/* 
* 获取下载时文件默认的文件名 
*/ 
public String getDownloadFileName() { 
String downloadFileName = fileName; 
try { 
downloadFileName = URLEncoder.encode(downloadFileName, "ISO-8859-1"); 
} catch (UnsupportedEncodingException e) { 
e.getMessage(); 
e.printStackTrace(); 
} 
return downloadFileName; 
} 
} 

<li> 
<a href="<%=path%>/download_DownLoadAction_downloadFile.action?fileName=dwr.jar">dwr.jar文件下在</a> 
</li> 
<li> 
<a href="<%=path%>/download_DownLoadAction_downloadFile.action?fileName=Struts2教程.pdf">Struts2教程.pdf文件下在</a> 
</li> 

<action name="download_*_*" class="com.wang.action.{1}" method="{2}"> 
<param name="inputPath">/upload</param> 
<!-- result type设置为stream --> 
<result name="download_success" type="stream"> 
<!-- MIME类型 --> 
<param name="contentType">application/octet-stream</param> 
<!-- inputName的值与action获取输入流资源的方法名相对应(action中定义getInputStream方法,并且返回类型为InputStream) --> 
<param name="inputName">inputStream</param> 
<!-- 设置带附件的文件 动态获取文件名(action中定义getDownloadFileName方法) --> 
<param name="contentDisposition">attachment;filename="${downloadFileName}"</param> 
<!-- 设置缓冲大小 --> 
<param name="bufferSize">2048</param> 
</result> 
</action>