概念：服务器端会话技术，在一次会话的多次请求间共享数据，将数据保存在服务器的对象中。HttpSession
快速入门：
获取HttpSession对象：
HttpSession session = request.getSession();
使用HttpSession对象：
Object getAttribute(String name)
void setAttribute（String name,Object value）
void removeAttribute(String name)
@WebServlet("/SessionDemo1")
public class SessionDemo1 extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session = request.getSession();
session.setAttribute("msg","hello session");
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
@WebServlet("/SessionDemo2")
public class SessionDemo2 extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session = request.getSession();
Object msg = session.getAttribute("msg");
System.out.println(msg);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
Session原理”
Session的实现是依赖Cookie的
