直接上代碼

@Component
public class LoginHandlerInterceptor implements HandlerInterceptor {

    //目標(biāo)方法執(zhí)行之前
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        Object user = request.getSession().getAttribute("currentUser");
        if (user == null) {
            //未登錄,返回登錄頁面
            response.sendRedirect("/LoginError.html");
            return false;
        }else {
            //放行
            return true;
        }
    }
}