package com.example.Maven.Project.intercepter;

import org.springframework.context.annotation.Bean;
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 CustomWebMvcConfigurer implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(getLoginInterceptor()).addPathPatterns("/api/v1/pri/**");//以"/api/v1/pri/**"结尾的都进行拦截
        WebMvcConfigurer.super.addInterceptors(registry);

    }

    //这个注释代码是视频未讲的，补充知识点哈
    //@Override
    //public void addInterceptors(InterceptorRegistry registry) {
    //
    //    registry.addInterceptor(getLoginInterceptor()).addPathPatterns("/api/v1/pri/**","/api/v1/pri/user/**")
    //      .excludePathPatterns("/**/*.html","/**/*.js"); //配置不拦截某些路径;
    //
    //
    //
    //    WebMvcConfigurer.super.addInterceptors(registry);
    //
    //
    //}
    @Bean
    public LoginIntercepter getLoginInterceptor(){
        return new LoginIntercepter();
    }
}

　　

package com.example.Maven.Project.intercepter;

import com.example.Maven.Project.domain.User;
import com.example.Maven.Project.service.impl.UserServiceImpl;
import com.example.Maven.Project.util.JsonData;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;

public class LoginIntercepter  implements HandlerInterceptor {
    private static final ObjectMapper objectMapper = new ObjectMapper();
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("LoginIntercepter preHandle =====");
        String token = request.getHeader("token");
        if(StringUtils.isEmpty(token)){
            token = request.getParameter("token");
        }


        if(!StringUtils.isEmpty(token)){

            //判断token是否合法
            User user = UserServiceImpl.sessionMap.get(token);

            if(user!=null){

                return true;
            }else {

                JsonData jsonData =  JsonData.buildError("登录失败，token无效",-2);
                String jsonStr = objectMapper.writeValueAsString(jsonData);
                renderJson(response,jsonStr);
                return false;

            }

        }else {

            JsonData jsonData =  JsonData.buildError("未登录",-3);
            String jsonStr = objectMapper.writeValueAsString(jsonData);
            renderJson(response,jsonStr);
            return false;
        }
    }

    private void renderJson(HttpServletResponse response,String json){

        response.setContentType("application/json");
        response.setCharacterEncoding("UTF-8");


        try(PrintWriter writer = response.getWriter()){
            writer.print(json);
        }catch (Exception e){
            e.printStackTrace();
        }

    }
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("LoginIntercepter postHandle =====");

        HandlerInterceptor.super.postHandle(request,response,handler,modelAndView);

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("LoginIntercepter afterCompletion =====");

        HandlerInterceptor.super.afterCompletion(request,response,handler,ex);
    }
}