struts 访问servlet api (ServletActionContext 方式)

    ServletActionContext  是ActionContext的子类，还实现了StrutsStatics接口，可以说ServletActionContext  就是为了struts 的action获得servlet相关api而设计的。

public class ServletActionContext extends ActionContext implements StrutsStatics

    ServletActionContext  提供了一些静态的方法来获得想要的 api 。

  PageContext ：

    public static PageContext getPageContext() {        return (PageContext) ActionContext.getContext().get(PAGE_CONTEXT);    }

  Request：

    public static HttpServletRequest getRequest() {        return (HttpServletRequest) ActionContext.getContext().get(HTTP_REQUEST);    }

  Response：

    public static HttpServletResponse getResponse() {        return (HttpServletResponse) ActionContext.getContext().get(HTTP_RESPONSE);    }

  ServletContext：

    public static ServletContext getServletContext() {        return (ServletContext) ActionContext.getContext().get(SERVLET_CONTEXT);    }

    下面仍然是一个登录测试的小例子：

package com.cd.action;import org.apache.struts2.ServletActionContext;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import java.io.IOException;public class LoginAction {    public String login()  {        //获取request对象        HttpServletRequest request =                (HttpServletRequest) ServletActionContext.getRequest();        Object username = request.getParameter("username");        Object password = request.getParameter("password");        if(username != null && password != null)        {            if("jack".equals(username)&&"jack".equals(password))            {                //获得session对象                HttpSession session = ServletActionContext.getRequest().getSession();                session.setAttribute("username",username);                return  "success";            }            else            {                //获得response对象                HttpServletResponse response = ServletActionContext.getResponse();                try                {                    response.getWriter().write("failed");                }                catch (IOException e)                {                    e.printStackTrace();                }                return  null;            }        }        else        {            //获得response对象            HttpServletResponse response =  ServletActionContext.getResponse();            try            {                response.getWriter().write("check input");            }            catch (IOException e)            {                e.printStackTrace();            }            return null;        }    }}

   xml配置，返回界面和测试结果和上一篇博客一样，这里就不贴出来了。