域對象的引用，ActionContext 和ServletActionContext類的使用

 

ActionContext 獲取 域引用的map

ServletActionContext獲取具體域對象

 

//域范圍

        ActionContext ac = ActionContext.getContext();
        Map<String,Object> applicationMap = ac.getApplication();//這個就是ServletContext對象中維護的那個Map
        applicationMap.put("p", "application_p");// ServletContext.setAttribute(key,object);
        
        Map<String,Object> sessionMap = ac.getSession();//這個就是HttpSession對象中維護的那個Map
        sessionMap.put("p", "session_p");// HttpSession.setAttribute(key,object);
        
        ac.put("p", "request_p");//相當於ServletRequest.setAttribute(key,obj);

 

//獲取Servlet中的常用對象的引用

//ServletContextAware接口

public class WebObjectAction extends ActionSupport implements Serializable,ServletContextAware,ServletRequestAware,ServletResponseAware {
    private ServletContext context;
    private HttpServletRequest request;
    private HttpServletResponse response;
    //方式一
    public String execute1(){
        ServletContext sc = ServletActionContext.getServletContext();
        System.out.println(sc);
        ServletRequest request = ServletActionContext.getRequest();
        System.out.println(request);
        return SUCCESS;
    }
    //方式二
    public String execute2(){
        System.out.println(context);
        System.out.println(request);
        System.out.println(response);
        return SUCCESS;
    }
    public void setServletContext(ServletContext context) {//如果動作類實現了ServletContextAware接口，就會自動調用該方法
        this.context = context;
    }
    public void setServletRequest(HttpServletRequest request) {
        this.request = request;
    }
    public void setServletResponse(HttpServletResponse response) {
        this.response = response;
    }

    
    
}