getServletContext()找不到这个路径

我的一开始的源码是：

public class BankInterceptor extends HandlerInterceptorAdapter {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        
         String username =  (String)request.getSession().getAttribute("adminusername");   
            if(username == null){
               
               response.sendRedirect(request.getServletContext().getContextPath()+"/admin/login");
                return false;  
            }else  
                return true;     
    }

下面是报错：

方法一：

getServletContext().getContextPath() 没有这个方法当然报错了。
你可以用request.getContextPath();

public class BankInterceptor extends HandlerInterceptorAdapter {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        
         String username =  (String)request.getSession().getAttribute("adminusername");   
            if(username == null){
               
               response.sendRedirect(request.getServletContext().getContextPath()+"/admin/login");
                return false;  
            }else  
                return true;     
    }

方法二：

在一开始的基础上加上.getSession()

public class BankInterceptor extends HandlerInterceptorAdapter {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        
         String username =  (String)request.getSession().getAttribute("adminusername");   
            if(username == null){
               
               response.sendRedirect(request.getSession().getServletContext().getContextPath()+"/admin/login");
                return false;  
            }else  
                return true;     
    }