攔截器：
    見字如意
正文：

定義一個實現了WebRequestInterceptor 接口的

package com.example.demo.Config;

import org.springframework.ui.ModelMap;
import org.springframework.web.context.request.WebRequest;
import org.springframework.web.context.request.WebRequestInterceptor;

/**
 * Created by Administrator on 2018/7/4.
 */
public class WebInterceptor implements WebRequestInterceptor {

    /**
     * 資源準備工作：WebRequest 的setAttribute(name, value, scope)
     *  Integer scope
     *      SCOPE_REQUEST=0 只有在當前request可以訪問
     *      SCOPE_SESSION=1 環境容許，局部隔離session，否則代普通session
     *      SCOPE_GLOBAL_SESSION=2 環境容許，全局共享session，否同上,貌似被取消了
     *
     * @param webRequest
     * @throws Exception
     */
    @Override
    public void preHandle(WebRequest webRequest) throws Exception {

        System.out.println("WebRequestInterceptor-----------------");
        webRequest.setAttribute("session","session",WebRequest.SCOPE_REQUEST);
        webRequest.setAttribute("session","session",WebRequest.SCOPE_SESSION);

    }

    /**
     * Controller后被調用，在視圖返回被渲染前被調用
     *
     * @param webRequest 傳遞整個請求數據
     * @param modelMap   controller處理后返回model對象
     * @throws Exception
     */
    @Override
    public void postHandle(WebRequest webRequest, ModelMap modelMap) throws Exception {

        System.out.println("java.util.ConcurrentModificationException: null");

    }

    /**
     * 請求處理完，視圖返回并渲染后，資源釋放
     *
     * @param webRequest 可以preHandle資源傳到這里釋放
     * @param e          當前請求的異常，已被spring處理則為null
     * @throws Exception
     */
    @Override
    public void afterCompletion(WebRequest webRequest, Exception e) throws Exception {

        System.out.println(e+"over---------------");

    }
}

定義繼承了HandlerInterceptorAdapter的攔截器

package com.example.demo.Config;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 攔截器
 * 繼承實現自定義攔截器
 * 發起請求進入攔截器鏈，先運行所有攔截器的preHandle方法
 * 當preHandle返回false則后面的攔截器不再執行（DispatcherServlet處理器認為已經處理完了請求）
 * 從當前攔截器往回執行所有攔截器的afterCompletion，當前的器的這個方法不會執行
 * 當preHandle全true，運行被攔截的controller
 * 進入攔截器鏈，運行所有攔截器的postHandle
 * 執行順序與preHandle相反，有機會修改ModelAndView
 * 往回執行afterCompletion
 * 順序與preHandle相反，用于清理資源
 * 攔截器拋出異常時，從當前器往回執行all器的afterCompletion
 * <p>
 * Created by Administrator on 2018/7/4.
 */
public class DemoInterceptor extends HandlerInterceptorAdapter {


    /*請求發生前發生*/
    public boolean preHandle(HttpServletRequest request,
                             HttpServletResponse response, Object handler) {
        long startTime = System.currentTimeMillis();
        request.setAttribute("startTime", startTime);
        return true;// 只有返回true才會繼續向下執行，返回false取消當前請求
    }

    /*請求發生完成后發生*/
    public void postHandle(HttpServletRequest request,
                           HttpServletResponse response, Object handler,
                           ModelAndView modelAndView) {
        long startTime = (long) request.getAttribute("startTime");
        request.removeAttribute("startTime");
        long endTime = System.currentTimeMillis();
        System.out.println("本次請求處理的時間為" + new Long(endTime - startTime) + "ms");
        request.setAttribute("handlingTime", endTime - startTime);
    }

    public void afterCompletion(HttpServletRequest request,
                                HttpServletResponse response, Object handler,
                                Exception ex) {
        System.out.println("在整個請求結束之后被調用,主要是用于進行資源清理工作");
    }

}

加入到項目中:WebMvcConfigurer

package com.example.demo.Config;

import org.aopalliance.intercept.Interceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.context.request.WebRequestInterceptor;
import org.springframework.web.servlet.config.annotation.*;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;

/**
 * 實現接口，重寫其方法對mvc配置
 * Created by Administrator on 2018/7/4.
 */
@Configuration
@EnableWebMvc//開啟支持
@ComponentScan("com.example.demo")
public class MyMVCConfig implements WebMvcConfigurer {

    @Bean
    public InternalResourceViewResolver viewResolver() {
        InternalResourceViewResolver viewResolver =
                new InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/classes/views/");
        viewResolver.setSuffix(".jsp");
        viewResolver.setViewClass(JstlView.class);
        return viewResolver;
    }

    public void addResourceHandlers(ResourceHandlerRegistry resourceHandlerRegistry) {
        //addResourceLocations文件放置目錄，Hander對外暴露訪問路徑
        resourceHandlerRegistry.addResourceHandler("/assets/**").addResourceLocations("classpath:/assets/");
    }

    @Bean
    public DemoInterceptor demoInterceptor() {
        return new DemoInterceptor();
    }

    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(demoInterceptor())
                .addPathPatterns("/**")
                .excludePathPatterns("/assest/**");//不需要攔截的路徑

        registry.addWebRequestInterceptor(webInterceptor());
    }

    @Bean
    public WebInterceptor webInterceptor() {
        return new WebInterceptor();
    }


}

效果圖：
訪問 http://localhost:8080/index

和上述 理論無差了

攔截器還是很簡單的

感謝分享：
《JavaEE開發的顛覆者Spring Boot實戰》
https://blog.csdn.net/u012420654/article/details/52098592
https://www.jianshu.com/p/f14ed6ca4e56
https://blog.csdn.net/gisam/article/details/78257991
https://www.cnblogs.com/softidea/p/6064064.html
https://blog.csdn.net/catoop/article/details/50501696

再附上盜來滴圖吧：源