Session对象的创建和获取 SessionServlet.java ~~~ package zyw.session; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import java.io.IOException; @WebServlet(name = "SessionServlet",urlPatterns = "/session") public class SessionServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //第一次访问时没有session，服务器会自动创建一个session对象 //之后再次访问的时候已经存在了session对象，这个直接获取这个对象 HttpSession session=request.getSession(); String sessionId=session.getId(); response.getWriter().write("JESSIONID"+sessionId); } } ~~~