struts2的開發（獲取ServletAPI對象）

方法一，通過ServletActionContext.類直接獲取：

public String rsa() throws Exception{
 HttpServletRequest request = ServletActionContext.getRequest();
 ServletContext servletContext = ServletActionContext.getServletContext();
 request.getSession()  
 HttpServletResponse response = ServletActionContext.getResponse();
 return "scope";
}

方法二，實現指定接口，由struts框架運行時注入：

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 setServletResponse(HttpServletResponse res) {
  this.response=res;
 }
 public void setServletContext(ServletContext ser) {
  this.servletContext=ser;
 }
}