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);

 }

}

public class ResourceFileUploadStatus {
 private long readedBytes = 0L;
 private long totalBytes = 0L;
 private int currentItem = 0;

 public long getReadedBytes() {

  return readedBytes;
 }
 public void setReadedBytes(long bytes) {
  readedBytes = bytes;
 }

 public long getTotalBytes() {
  return totalBytes;
 }
 public void setTotalBytes(long bytes) {
  totalBytes = bytes;
 }
 public int getCurrentItem() {
  return currentItem;

 }

 public void setCurrentItem(int item) {
  currentItem = item;

 }

}

public void parse(HttpServletRequest servletRequest, String saveDir)
  throws IOException {

 System.out.println("执行自定义MultiPartRequest");
  DiskFileItemFactory fac = new DiskFileItemFactory();
  // Make sure that the data is written to file
  fac.setSizeThreshold(0);
  if (saveDir != null) {
   fac.setRepository(new File(saveDir));
  }

  // Parse the request

  try {

   ServletFileUpload upload = new ServletFileUpload(fac);
   upload.setSizeMax(maxSize);

   ResourceProgressListener progressListener = new ResourceProgressListener(servletRequest);//新建一个监听器

    upload.setProgressListener(progressListener);//添加自己的监听器

   List items = upload.parseRequest(createRequestContext(servletRequest));

    for (Object item1 : items) {

    FileItem item = (FileItem) item1;
    if (LOG.isDebugEnabled()) LOG.debug("Found item " + item.getFieldName());
    if (item.isFormField()) {
     LOG.debug("Item is a normal form field");
     List<String> values;
     if (params.get(item.getFieldName()) != null) {
      values = params.get(item.getFieldName());
     } else {

      values = new ArrayList<String>();

     }
     String charset = servletRequest.getCharacterEncoding();
     if (charset != null) {
      values.add(item.getString(charset));
     } else {

      values.add(item.getString());
     }

     params.put(item.getFieldName(), values);

    } else {

     LOG.debug("Item is a file upload");

 

     // Skip file uploads that don't have a file name - meaning that no file was selected.
     if (item.getName() == null || item.getName().trim().length() < 1) {
      LOG.debug("No file has been uploaded for the field: " + item.getFieldName());
      continue;

     }
 

     List<FileItem> values;
     if (files.get(item.getFieldName()) != null) {
      values = files.get(item.getFieldName());
     } else {
      values = new ArrayList<FileItem>();

     }

 

     values.add(item);
     files.put(item.getFieldName(), values);
    }
   }
  } catch (FileUploadException e) {
   LOG.warn("Unable to parse request", e);
   errors.add(e.getMessage());

  }

} 

<bean type="org.apache.struts2.dispatcher.multipart.MultiPartRequest" name="requestParser"
 class="com.zeige.ResourceMultiPartRequest" scope="default" optional="true" />
<constant name="struts.multipart.handler" value="requestParser" />