九、在动作类中访问ServletAPI

九、在动作类中访问ServletAPI

1、方式一：（简单，推荐使用）ServletActionContext

public String execute() throws Exception {

        //获取Servlet的相关对象引用，HttpServletRequest HttpSession HttpServletResponse ServletContext

        //PageContext等等

        HttpServletRequest request = ServletActionContext.getRequest();

        PageContext pc = ServletActionContext.getPageContext();

        HttpServletResponse response = ServletActionContext.getResponse();

        ServletContext sc = ServletActionContext.getServletContext();

        HttpSession session = request.getSession();

        //打印相关对象引用

        System.out.println(request);

        System.out.println(pc);

        System.out.println(response);

        System.out.println(sc);

        System.out.println(session);

        return "none";

    }

 

 

1. 方式二：（麻烦）

   动作类实现特定的接口。就必须实现特定的方法，调用动作方法前，框架会把响应的对象给注入进来。

   public class UserAction implements ServletRequestAware, ServletResponseAware, ServletContextAware {

       private HttpServletRequest request;

       private HttpServletResponse response;

       private ServletContext sc;

       public String execute() {

           //打印相关对象引用

           System.out.println(request);

           System.out.println(response);

           System.out.println(sc);

           return "none";

       }

    

       //在调用动作方法执行前，框架会把ServletContext对象给注入进来

       @Override

       public void setServletContext(ServletContext sc) {

           this.sc = sc;

           

       }

       //在调用动作方法执行前，框架会把HttpServletResponse对象给注入进来

       @Override

       public void setServletResponse(HttpServletResponse response) {

           this.response = response;

           

       }

       //在调用动作方法执行前，框架会把HttpServletRequest对象给注入进来

       @Override

       public void setServletRequest(HttpServletRequest request) {

           this.request = request;

           

       }

   }

    

    

   原理：是一个拦截器给你注入进来的。struts-default.xml

   <interceptor name="servletConfig" class="org.apache.struts2.interceptor.ServletConfigInterceptor"/>

   一看源码便知。