Struts2实现文件上传时显示进度条功能

import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpSession;import org.apache.commons.fileupload.ProgressListener;public class ResourceProgressListener implements ProgressListener { private HttpSession session; public ResourceProgressListener(HttpServletRequest request) {  session = request.getSession();  ResourceFileUploadStatus newUploadStatus = new ResourceFileUploadStatus();  session.setAttribute("currentUploadStatus", newUploadStatus); } public void update(long readedBytes, long totalBytes, int currentItem) {  ResourceFileUploadStatus status = (ResourceFileUploadStatus) session.getAttribute("currentUploadStatus");  status.setReadedBytes(readedBytes);  status.setTotalBytes(totalBytes);  status.setCurrentItem(currentItem); }}