how to deploy a webapp in tomcat using IDEA

I'm a new javaer. I am trying to develop a webapplication and deploy in tomcat. I just use the template created by idea, but it works not well.

I'm using tomcat9.0.41.

HelloServlet.java

import java.io.*;

import jakarta.servlet.http.*;
import jakarta.servlet.annotation.*;

@WebServlet(name = "helloServlet", value = "/hello-servlet")
public class HelloServlet extends HttpServlet {
    private String message;

    public void init() {
        message = "Hello World!";
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        response.setContentType("text/html");

        // Hello
        PrintWriter out = response.getWriter();
        out.println("<html><body>");
        out.println("<h1>" + message + "</h1>");
        out.println("</body></html>");
    }

    public void destroy() {
    }
}

when I open http://localhost:8080/serv01_war_exploded/ in chrome, it works well and shows the content in index.jsp. But when I try to open http://localhost:8080/serv01_war_exploded/hello-servlet, it returns 404 error.

All the above happens in windows10 system.

So what caused this problem, idea or tomcat or some other things?