使用SmartUpload上傳文件沒有報錯，但save時返回的值是0，為什么？

SmartUpload su=new SmartUpload();

su.initialize(getServletConfig(), request, response);

su.setMaxFileSize(1024*1024*10);

su.setTotalMaxFileSize(1024*1024*100);

su.setAllowedFilesList("jpg,jpeg,bmp,png,gif");

String saveFilePath=getServletContext().getRealPath("/")+"uploadFile";

try {

su.upload();

File path=new File(saveFilePath);

if(!path.exists()){

path.mkdir();

}

int uploadCount=su.save(saveFilePath);

request.getSession().setAttribute("result", "上傳成功"+uploadCount);

response.sendRedirect("collectIdea.jsp");