struts2的java文件中不能直接弹出script对话框

需要引入接口

ServletResponseAware

 public class Login extends ActionSupport implements SessionAware,ServletResponseAware
 {

     private HttpServletResponse response = null;
 　　　　....
     public void setServletResponse(HttpServletResponse response) {
         // TODO Auto-generated method stub
         this.response = response;
     }

     public String execute()
     {
         Person person = new Person();
         PersonDAO personDAO = new PersonDAO();
         if(personDAO.findById(id)==null)
         {
             System.out.println("用户不存在");
             try {
                 response.setContentType("text/html; charset=UTF-8");
                 response.setCharacterEncoding("UTF-8");        //防止乱码；
                 PrintWriter out = response.getWriter();
                 out.print("<Script>alert('用户不存在!')</Script>");
                 out.flush();
                 out.close();
             }
             catch (IOException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }
     ....
     }
 }
             

不过很多网页，像淘宝之类的，他们的页面出错不是这么处理的，这种方法弹出提示框以后不能再返回页面