1.ServletContext作用于整个APP
1 //获取ServletContext对象 2 ServletContext servlet = this.getServletContext(); 3 servlet.setAttribute("name","zhangsan");
2.session
备注： session是服务器端对象，保存在服务器端。并且服务器可以将创建session后产生的sessionid通过一个cookie返回给客户端，以便下次验证。（session底层依赖于cookie）
3.request
三大对象获取方式：
1 class Demo extends HttpServlet { 2 @Override 3 protected void doGet(HttpServletRequest req, HttpServletResponse resp) { 4 5 //获取Session对象存储数据 6 HttpSession session = req.getSession(); 7 session.setAttribute("name","zhangsan"); 8 9 //获取ServletContext对象存储数据 10 ServletContext servlet = this.getServletContext(); 11 servlet.setAttribute("name","zhangsan"); 12 13 //通过session对象获取ServletContext 14 ServletContext servlet1 = session.getServletContext(); 15 servlet1.setAttribute("name","zhangsan"); 16 17 //通过request直接存储数据 18 req.setAttribute("name","zhangsan"); 19 } 20 @Override 21 protected void doPost(HttpServletRequest req, HttpServletResponse resp){ 22 this.doGet(req,resp); 23 } 24 }
原文：https://www.cnblogs.com/monkey1024/p/11490344.html