package com.xc.boot.handler;

import org.springframework.stereotype.Component;

import org.springframework.web.servlet.HandlerInterceptor;

import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

@Component

public class CustomInterceptor implements HandlerInterceptor {

    /**

     * 预处理回调方法，实现处理器的预处理（如登录检查），第三个参数为响应的处理器；

     * 返回值：true表示继续流程（如调用下一个拦截器或处理器）；

     * false表示流程中断（如登录检查失败），不会继续调用其他的拦截器或处理器，此时我们需要通过response来产生响应；

     */

    @Override

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        System.out.println("===========CustomInterceptor preHandle");

        return true;

    }

    /**

     * 整个请求处理完毕回调方法，即在视图渲染完毕时回调，如性能监控中我们可以在此记录结束时间并输出消耗时间，

     * 还可以进行一些资源清理，类似于try-catch-finally中的finally

     */

    @Override

    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

        System.out.println("===========CustomInterceptor postHandle");

    }

    /**

     * 后处理回调方法，实现处理器的后处理（但在渲染视图之前），此时我们可以通过modelAndView（模型和视图对象）对模型数据进行处理或对视图进行处理

     */

    @Override

    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

        System.out.println("===========CustomInterceptor afterCompletion");

    }

}

package com.xc.boot.config.control;

import com.xc.boot.handler.CustomInterceptor;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.context.annotation.Configuration;

import org.springframework.web.servlet.config.annotation.InterceptorRegistry;

import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration

public class InterceptorConfig implements WebMvcConfigurer {

    @Autowired

    private CustomInterceptor customInterceptor;

    @Override

    public void addInterceptors(InterceptorRegistry registry) {

        registry.addInterceptor(customInterceptor).addPathPatterns("/**");

    }

}