后端拦截器

package com.huoziqi.springboot.common.config;

import com.huoziqi.springboot.common.handler.LoginInterceptor;
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;

/**
 * 拦截器
 * @version 1.0
 * @Author 作者名
 * @Date 2022/10/21 22:29
 */
@Configuration
public class InterceptorConfig implements WebMvcConfigurer {

    @Bean
    public LoginInterceptor loginInterceptor(){
        return new LoginInterceptor();
    }


    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        System.out.println("[idea] =====>> 拦截一次");
        // 在@Configration注解生效时不会爆红
        // 拦截所有请求判断token是否合法决定是不是要登录
        
        registry.addInterceptor(loginInterceptor())
                .addPathPatterns("/**")
                .excludePathPatterns("/login","/register","/file/upload")
                .excludePathPatterns("/user/export","/login/**","/file/**");
    }


}

登录拦截

/**
 * 拦截器功能
 * 对token进行验证
 */
//@Component
public class LoginInterceptor implements HandlerInterceptor {

    @Resource
    UserMapper userMapper;

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

        //如果不是映射到方法直接通过
        if(!( handler instanceof HandlerMethod)){
            return true;
        }

        //获取前端传递过来的token
        String token = request.getHeader("token");
        System.out.println("token_is" + token);  //================================

        // token非空校验
        if(StringUtils.isBlank(token)){
            throw new ServiceExceptin(Constans.CODE_401,"没有token 请重新登录");
        }

        // 根据token获取id进行验证

        Map<String, Object> map = JWTUtils.checkToken(token);

        Integer id =(Integer) map.get("userId");

        User user = userMapper.selectById(id);

        // user存到UserThreadLocal
        UserThreadLocal.put(user);

        if(user == null){
            throw new ServiceExceptin(Constans.CODE_401,"登陆过期，重新登录");
        }


        /**
         * 登陆拦截逻辑
         * 前端请求路径时判断token
         * token == null  不放行
         * token ！= null 放行
         * 通过token验证user信息合法性
         * user == null 重新登录，可能是token过期了
         * user != null 放行
         */
        return true;
    }
}