Struts 2对Servlet API进行了封装，是业务层更加独立，如果需要调用Request、Response等Servlet API有两种途径

利用ServletActinContext的静态方法

Struts 2利用ServletActinContext来维护Servlet对象，ServletActinContext利用ThreadLocal来维护不同 线程的Servlet对象，因此可以使用ServletActinContext来获得Servlet的各种对象

    import  org.apache.struts2. ServletActinContext        public  class  LoginActin extends ActionSupport{                       public String login(){                     HttpServletRequest request = ServletActinContext.getRequest();                     HttpServletResponse response = ServletActinContext.getResponse();                     HttpServletContext context = ServletActinContext.getServletContext();                     HttpSession session = request.getSession();                     ……              }                     }  

利用相关的Aware接口

Struts 2在实例化一个Action实例时，如果发现它实现了相关的Aware接口，会把相应的资源通过Aware接口方法注射进去，Aware接口其实是一种拦截器

Servlet API常用对象application、request、response、session对应的Aware接口分别为 ServletContextAware、ServletRequestAware、ServletResponseAware、 SessionAware

    public class ServletAwareAction extends ActionSupport implementsServletContextAware,ServletRequestAware,ServletResponseAware,SessionAware{                       private HttpServletRequest request ;              private HttpServletResponse response;              private HttpServletContext application;              private HttpSession session ;                 //相应的setter方法              public void setServletRequest(HttpServletRequest request ){                     this.request = request;              }              public void setServletResponse(HttpServletResponse response ){                     this.reponse = reponse;              }              public void setServletContext(HttpServletContext application ){                     this. application = application;              }              public void setSession(Map sessionValues){                     this.session = sessionValues;              }        //然后可以在Action中直接使用这些对象              public String execute(){                     request.getRemoteAddr();                     response.getContentType()                     session.get(“account”);                     return SUCCESS;              }        }