Struts2之获取Web元素

Struts2中提供了4种获取Web元素的方式
1.方式1 使用ServletActionContext 
HttpServletRequest request = ServletActionContext.getRequest();
HttpServletResponse response=ServletActionContext.getResponse();

2.方式2 实现2个接口 ServletRequestAware ServletResponseAware  注入的概念
每一次在调用你要访问的方法时 都会先执行 setServletRequest setServletResponse 这两个方法
setServletRequest 由struts2 实例化HttpServletRequest后给你
setServletResponse 由struts2 实例化HttpServletResponse后给你
public class xxAction implements ServletRequestAware,ServletResponseAware
private HttpServletRequest request;
private HttpServletResponse response;
public String index(){
}
public void setServletRequest(HttpServletRequest httpServletRequest) {  
    this.request=httpServletRequest;
}
public void setServletResponse(HttpServletResponse httpServletResponse) {
  this.response=httpServletResponse;
}

3.struts2使用Map模拟的第一种方式 使用Map来模拟HttpServletRequest 类 放东西
private Map<String,Object> request;  //httpservletrequest
private Map<String,Object> session;  //httpsession
private Map<String,Object> application; //servletContext
//使用map的方式 只能往页面传递参数  不能像HttpServletRequest HttpSession使用它们的方法
public Login3Action() {
    request= (Map<String, Object>) ActionContext.getContext().get("request");
    session=ActionContext.getContext().getSession();
    application=ActionContext.getContext().getApplication();
}
//使用map的方式 因为map是一个容器 只能存放/设置数据 就不是setAttribute 而是put
public String index()
{
   request.put("uname","张三");
   session.put("usex","男");
   return "index";
}

4.struts2使用map模拟的第2种方式
需要继承RequestAware,SessionAware,ApplicationAware 3个常用的接口
public class Login4Action implements RequestAware,SessionAware,ApplicationAware {
    private Map<String,Object> request;
    private Map<String,Object> session;
    private Map<String,Object> application;
    public String index()
    {
       request.put("uname","李四");
       session.put("usex","女");
       return "index";
    }
    public void setApplication(Map<String, Object> map) {
        this.application=map;
    }
    public void setRequest(Map<String, Object> map) {
      this.request=map;
    }
  public void setSession(Map<String, Object> map) {
    this.session=map;
    }