Session会话跟踪技术

package com.csdn.servlet;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;
import java.io.IOException;
@WebServlet("/h11")
public class SessionServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException
    {
        //获取Session对象，如果有，则直接返回，如果没有，则创建一个新的
        HttpSession session = req.getSession();
        System.out.println(session.isNew());
        System.out.println(session.getId());
    }
}