如何获取 HttpServletRequest 、HttpSession、ServletContext 、HttpServletResponse

如何获取 HttpServletRequest 、HttpSession、ServletContext 、HttpServletResponse：
方法一，通过ServletActionContext类直接获取：
public String rsa() throws Exception{
 HttpServletRequest request = ServletActionContext.getRequest();
 ServletContext servletContext = ServletActionContext.getServletContext();
 request.getSession();
 HttpServletResponse response = ServletActionContext.getResponse();
 return "success";
}

方法二，实现指定接口，由struts运行时注入：
public class HelloWorldAction implements ServletRequestAware, ServletResponseAware,ServletContextAware{
 private HttpServletRequest request;
 private ServletContext servletContext;
 private HttpServletResponse response;
 public void setServletRequest(HttpServletRequest req){
  this.request = req;
 }
 public void setServletContext(ServletContext context){
  this.servletContext = context;
 }
 public void setServletResponse(HttpServletResponse response){
  this.reponse = response;
 }
}

 

方法三，由ActionContext获取
public String execute() throws Exception{
 ActionContext ctx = ActionContext.getContext();
 ctx.getApplication().put("app", "应用范围");
 ctx.getSession().put("see", "session范围");
 ctx.put("req", "request范围");
 return "success";
}