会话拦截器，用于在请求一些接口之前，统一去拦截请求，进行验证等操作。

package com.sample.controller.interceptor;
import org.springframework.web.servlet.HandlerInterceptor;

public class UserTokenInterceptor implements HandlerInterceptor {
    
    /**
     * 拦截请求，在访问controller调用之前
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, 
                             HttpServletResponse response,
                             Object handler){
         
    }
    
    /**
     * 请求访问controller之后，渲染视图之前
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    /**
     * 请求访问controller之后，渲染视图之后
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @throws Exception
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}

以上配置好之后，还需要将拦截器注册一下才可使用。