jakarta Servlet cannot use ServletFileUpload.parseRequest() to convert HttpRequest obj to List obj

Question

When I learn how to use servlet to achieve file uploading, I met this problem. details are as follows, my full code:

import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.RequestContext;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import java.io.*;
import java.util.List;

public class UploadServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    public void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        try {
            // set Content-Type
            resp.setHeader("Content-type", "text/html;charset=UTF-8");
            // create DiskFileItemFactory object
            DiskFileItemFactory factory = new DiskFileItemFactory();
            // set file temporary storage path, if the path does not exist, create it
            factory.setRepository(new File("D:\\source\\jsp\\fileupdown\\temp"));
            if (!factory.getRepository().exists()) {
                factory.getRepository().mkdirs();
            }
            // set ServletFileUpload object
            ServletFileUpload upload = new ServletFileUpload(factory);
            // set character encoding
            upload.setHeaderEncoding("UTF-8");
            // analyze request, get file item list
            List<FileItem> fileitems = upload.parseRequest(req);
            // get byte stream
            PrintWriter writer = resp.getWriter();
            // traverse file item list
            for (FileItem fileitem : fileitems) {
                // if it is a form field
                if (fileitem.isFormField()) {
                    // get field name
                    String name = fileitem.getFieldName();
                    if (name.equals("name")) {
                        if (fileitem.getString("UTF-8").equals("")) {
                            writer.println("name can not be empty");
                        } else {
                            writer.println("name:" + fileitem.getString("UTF-8"));
                        }
                    }
                } else {
                    // get file name
                    String filename = fileitem.getName();
                    // process file
                    if (filename != null && !filename.equals("")) {
                        writer.print("uploaded file:" + filename + "<br>");
                        filename = filename.substring(filename.lastIndexOf("\\") + 1);
                        // unique file name
                        String uniqueFileName = System.currentTimeMillis() + "_" + filename;
                        // create same name file in server
                        String webPath = "/upload/";
                        String realPath = getServletContext().getRealPath(webPath + uniqueFileName);
                        // create file
                        File file = new File(realPath);
                        file.getParentFile().mkdirs();
                        file.createNewFile();
                        // get UploadStream
                        InputStream in = fileitem.getInputStream();
                        // use FileOutputStream to write file
                        FileOutputStream out = new FileOutputStream(file);
                        // create buffer
                        byte[] buffer = new byte[1024];
                        int len = 0;
                        // read file
                        while ((len = in.read(buffer)) > 0) {
                            out.write(buffer, 0, len);
                        }
                        in.close();
                        out.close();
                        writer.println("upload successfully");
                    } else {
                        writer.println("file can not be null");
                    }
                }
            }
        } catch (FileUploadException e) {
            throw new RuntimeException(e);
        }
    }

}

the error:

java: Cannot access javax.servlet.http.HttpServletRequest
Cannot find class file of javax.servlet.http.HttpServletRequest

the code that reports the error:

// set ServletFileUpload object
ServletFileUpload upload = new ServletFileUpload(factory);
// set character encoding
upload.setHeaderEncoding("UTF-8");
// analyze request, get file item list
List<FileItem> fileitems = upload.parseRequest(req);

I have tried to rewrite the code as follows:

// set ServletFileUpload object
ServletFileUpload upload = new ServletFileUpload(factory);
// set character encoding
upload.setHeaderEncoding("UTF-8");
// analyze request, get file item list
List<FileItem> fileitems = upload.parseRequest((RequestContext) req);

but it still cannot work.

I think the error comes from the difference between package javax and jakarta. The acticles teching how to use servlet to upload file use the old version servlet in javax while i use servlet in jakarta. However, I searched for a long time on the Internet and could not find a way to solve the error without changing the jakarta to javax.

Thx for your help.