Java Struts2 接口如何获取POST过来的文件？

private File[] upload;
private String[] uploadFileName;
if (upload != null) {
    String fileNames = "";
            String fileAdds = "";
            try {
                for (int i = 0; i < upload.length; i++) {
                    InputStream is = new FileInputStream(upload[i]);
                    String epName = uploadFileName[i].substring(uploadFileName[i].lastIndexOf("."));
                    String fileName = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date()).toString() + i + epName;
                    String path = this.getServletRequest().getServletContext().getRealPath("/uploadfile/committee")+ "/" + fileName;
                    OutputStream os = new FileOutputStream(path);
                    byte buffer[] = new byte[(int) upload[i].length()];
                    int count = 0;
                    while ((count = is.read(buffer)) > 0) {
                        os.write(buffer, 0, count);
                    }
                    os.close();
                    is.close();
                    fileNames += uploadFileName[i] + "|";
                    fileAdds += "uploadfile/committee/" + fileName + "|";
                }
            } catch (Exception e) {
            }
            advice.setFileNames(fileNames);
            advice.setFileAdds(fileAdds);
        }