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