域对象的引用，ActionContext 和ServletActionContext类的使用

ActionContext 获取 域引用的map

ServletActionContext获取具体域对象

//域范围

        ActionContext ac = ActionContext.getContext();

        Map<String,Object> applicationMap = ac.getApplication();//这个就是ServletContext对象中维护的那个Map

        applicationMap.put("p", "application_p");// ServletContext.setAttribute(key,object);

Map<String,Object> sessionMap = ac.getSession();//这个就是HttpSession对象中维护的那个Map

        sessionMap.put("p", "session_p");// HttpSession.setAttribute(key,object);
ac.put("p", "request_p");//相当于ServletRequest.setAttribute(key,obj);

 1 //获取Servlet中的常用对象的引用

 2

 3 //ServletContextAware接口

 4

 5 public class WebObjectAction extends ActionSupport implements Serializable,ServletContextAware,ServletRequestAware,ServletResponseAware {

 6     private ServletContext context;

 7     private HttpServletRequest request;

 8     private HttpServletResponse response;

 9     //方式一

10     public String execute1(){

11         ServletContext sc = ServletActionContext.getServletContext();

12         System.out.println(sc);

13         ServletRequest request = ServletActionContext.getRequest();

14         System.out.println(request);

15         return SUCCESS;

16     }

17     //方式二

18     public String execute2(){

19         System.out.println(context);

20         System.out.println(request);

21         System.out.println(response);

22         return SUCCESS;

23     }

24     public void setServletContext(ServletContext context) {//如果动作类实现了ServletContextAware接口，就会自动调用该方法

25         this.context = context;

26     }

27     public void setServletRequest(HttpServletRequest request) {

28         this.request = request;

29     }

30     public void setServletResponse(HttpServletResponse response) {

31         this.response = response;

32     }

33

34

35

36 }

域对象的引用，ActionContext 和ServletActionContext类的使用