ActionContext(struts 建议的) action的上下文对象
//ActionContext可以理解为HttpServletRequest的代理
ActionContext acx= ActionContext.getContext();
Map<String,Object> map= acx.getParameters();
String[] s=(String[])map.get("userName");
// request.setAttribute("hero","joke");
acx.put("hero","joke");
//request.getAttribute("hero");
acx.get("hero")
//session 就是HttpSession的代理
Map<Stirng,Object> session=acx.getSession();
// session.setAttribute("hero","joke");
session.put("hero","joke");
//session.getAttribute("hero");
session.get("hero")
//app就是ServletContextd的代理
Map<String,Object> app=acx.getApplication();
app.put("a","aa");
app.get("a");
ServletActionContext(获取真的httpServletRequest)
HttpServletRequest request = ServletActionContext.getRequest();
String name = request.getParameter("userName");
request.setAttribute("hero", "水晶");
HttpSession session = request.getSession();
session.setAttribute("s", "session");
session.getAttribute("s");
ServletContext sc = request.getServletContext();
sc.setAttribute("a", "app");