// Check that we have a file upload request 檢查是否是表單檔案上請求
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
// Create a new file upload handler 建立上傳物件
ServletFileUpload upload = new ServletFileUpload();

// Parse the request
FileItemIterator iter = upload.getItemIterator(request); //得到所有的上傳資料
while (iter.hasNext()) { //迴圈上傳表單的元素
    FileItemStream item = iter.next();
    String name = item.getFieldName(); //得到元素名
    InputStream stream = item.openStream();
    if (item.isFormField()) { //如果是普通元素，列印元素名與值
        System.out.println("Form field " + name + " with value "
            + Streams.asString(stream) + " detected.");
    } else {//如果是檔案型的元素，列印元素名與檔名
        System.out.println("File field " + name + " with file name "
            + item.getName() + " detected.");
        // Process the input stream
        ...//儲存檔案
    }
}