Java 如何使用ExtJs将参数发送到服务器？

Im将文件上载到服务器并发送参数。但我有两个问题

1无法发送参数。我有：

      handler: function(){
        mapinfo="mapinfo";
        formp.getForm().submit({
        url: url_servlet+'uploadfile',
        params: {file_type: mapinfo},
        success: function(formp, o) {
           alert(o.result.file);
           kad_tab.getStore().reload()
           zoom_store.load();
        }
    })
}

和服务器端：

public class uploadfile extends HttpServlet implements Servlet
{
public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, java.io.IOException {
    response.setCharacterEncoding("UTF-8");
    response.setContentType("text/html");
    String st = request.getParameter("file_type");
    PrintWriter writer = response.getWriter();
    boolean isMultipart = ServletFileUpload.isMultipartContent(request);
    if (!isMultipart) {
            return;
        }          
  FileItemFactory factory = new DiskFileItemFactory();
    ServletFileUpload upload = new ServletFileUpload(factory);
    List<FileItem> list=null;
    String mifpath= "1";
    String path = " ";
    String mif = " ";
    String from = "\\\\";
    String to ="/";
    String error="";
     try{
      list = upload.parseRequest(request);
      Iterator<FileItem> it = list.iterator();
      response.setContentType("text/html");
      while ( it.hasNext() ) 
      {

        FileItem item = (FileItem) it.next();
        File disk = new File("C:/uploaded_files/"+item.getName());

            path = disk.toString();
            String code = new String(path.substring(path.lastIndexOf("."), path.length()).getBytes("ISO-8859-1"),"utf-8");
            if (code.equalsIgnoreCase(".zip"))
            {
                mifpath=path;
                mif = mifpath.replaceAll(from, to);
                item.write(disk);
                //error=unzip.unpack(mif, "C:/uploaded_files");
            }
            else
            {
                error = "Выбранный файл не является архивом zip";

            }
      }
    }

     catch ( Exception e ) {
      log( "Upload Error" , e);
    }
     System.out.println("st="+st);
    writer.println("{success:true, file:'"+error+"'}");
    writer.close();
}
}

---

如果我在服务器端执行此操作，则不会有任何效果。例如，如果我上传的不是zip文件，我会得到警告，说它不是zip文件，但没有得到它。如果我没有在面板上添加combobox，我会收到此警报。怎么了？

这是因为请求是多部分的。然后，您不能使用以下命令读取参数： 字符串st=request.getParameter（“文件类型”）

因为它总是空的。相反，请使用以下snipet：

List items = upload.parseRequest(request);
Iterator iter = items.iterator();
while (iter.hasNext()) {
    FileItem item = (FileItem) iter.next();

    if (item.isFormField()) {
        processFormField(item);
    } else {
        processUploadedFile(item);
    }
}

关于你的第二个问题，我不明白

List items = upload.parseRequest(request);
Iterator iter = items.iterator();
while (iter.hasNext()) {
    FileItem item = (FileItem) iter.next();

    if (item.isFormField()) {
        processFormField(item);
    } else {
        processUploadedFile(item);
    }
}