<s:form action="testUpload" enctype="multipart/form-data">
  <s:textfield name="userName[0]" label="用户-1"></s:textfield>
  <s:file name="photos" label="照片"></s:file>
  <s:textfield name="userName[1]" label="用户-2"></s:textfield>
  <s:file name="photos" label="照片"></s:file>
  <s:textfield name="userName[2]" label="用户-3"></s:textfield>
  <s:file name="photos" label="照片"></s:file>
  <s:submit value="提交"></s:submit>
</s:form> 

public class UploadAction extends ActionSupport{

  @Setter@Getter
  private List<File> photos;
  @Setter@Getter
  private List<String> photosContentType;
  @Setter@Getter
  private List<String> photosFileName;
  @Setter@Getter
  private List<String> userName;

  public String testUpload() throws IOException {
    System.out.println("userName: "+userName);
    System.out.println("photos: "+photos);
    System.out.println("photosFileName: "+ photosFileName);
    System.out.println("photosContentType: "+photosContentType);

    // 将文件传到服务器根目录下upload文件下
    // 获取ServletContext
    ServletContext servletContext = ServletActionContext.getServletContext();
    //获取真实路径
    String realPath = servletContext.getRealPath("/upload");
    System.out.println(realPath);
    File uploadFile = new File(realPath);
    //判断路径是否存在
    if (!uploadFile.exists()){
      //不存在创建
      uploadFile.mkdir();
    }
    for (int i = 0; i < photos.size(); i++) {
      UUID uuid = UUID.randomUUID();
      FileUtils.copyFile(photos.get(i), new File(realPath + "/" + uuid + photosFileName.get(i)));
    }
    return SUCCESS;
  }
}

<constant name="struts.devMode" value="true"/>

 <!-- 在这修改总文件的的大小 -->
 <constant name="struts.multipart.maxSize" value="2097152"/>
 <package name="default" namespace="/" extends="struts-default">
  <interceptors>
    <interceptor-stack name="myInterceptor">
      <interceptor-ref name="defaultStack">
        <!-- 修改单个文件大小，Commons FileUpload 组件默认接受上传文件总的最大值为 2M -->
        <param name="fileUpload.maximumSize">57,408</param>
        <!-- 允许上传的文件类型 -->
        <param name="fileUpload.allowedTypes">image/pjpeg,image/gif</param>
        <!-- 允许上传文件的扩展名 -->
        <param name="fileUpload.allowedExtensions">jpg,gif</param>
      </interceptor-ref>
    </interceptor-stack>
  </interceptors>

  <default-interceptor-ref name="myInterceptor"></default-interceptor-ref>
  
  <action name="testUpload" class="org.pan.action.UploadAction" method="testUpload">
    <result name="success">/WEB-INF/views/success.jsp</result>
    <result name="input">/upload.jsp</result>
  </action>
</package>

struts.messages.error.file.too.large=你传的文件太大了
struts.messages.error.content.type.not.allowed=文件类型错误
struts.messages.error.file.extension.not.allowed=扩展名错误
struts.messages.upload.error.SizeLimitExceededException=文件总大小超过上限

<a href="testDownLoad">下载</a>

public class DownLoadAction extends ActionSupport{
  //通常以下这几个参数会在Action 中提供
  @Setter@Getter
  private String contentType;
  @Setter@Getter
  private long contentLength;
  @Setter@Getter
  private String contentDisposition;
  @Setter@Getter
  private InputStream inputStream;

  public String testDownLoad() throws FileNotFoundException, UnsupportedEncodingException {
    //获取ServletContext
    ServletContext servletContext = ServletActionContext.getServletContext();
    //获取文件的路径
    String realPath = servletContext.getRealPath("/WEB-INF/file/至少还有你.mp3");
    //获取文件的流
    inputStream = new FileInputStream(realPath);
    //设置文件的类型
    contentType = servletContext.getMimeType(realPath);
    //获取文件的长度
    contentLength = new File(realPath).length();
    //设置文件名
    String fileName = "至少还有你.mp3";
    fileName = new String(fileName.getBytes("gbk"),"iso8859-1");
    contentDisposition = "attachment;filename="+fileName;
    return SUCCESS;
  }
}

<!-- 文件下载 -->
<action name="testDownLoad" class="org.pan.action.DownLoadAction" method="testDownLoad">
  <result type="stream">
    <!-- 文件缓冲大小 -->
    <param name="bufferSize">2048</param>
  </result>
</action>