问题

上一篇博客中提到使用redis来存用户的登录信息，解决了session不共享问题。

在拦截器中，重新设置了用户信息的有效期，保证只要用户一直请求就永不过期。但是并不是每个请求都会经过拦截器的（因为登录拦截器，不是每个请求都需要验证登录），那么就会导致用户比如一直在访问不会经过拦截器的请求，突然就会提示用户未登录，这就不合适了。

解决

新添加一个拦截器，专门用于拦截所有请求，只用于获取token,获取用户信息，将用户信息放入redis,刷新token的有效期，放行。

小提示

 redis客户端工具可以查看key的有效期。

实现思路图

 刷新token的拦截器

package com.xkj.org.interceptor;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.map.MapUtil;
import cn.hutool.core.util.StrUtil;
import com.xkj.org.dto.UserDTO;
import com.xkj.org.utils.RedisConstants;
import com.xkj.org.utils.SystemConstants;
import com.xkj.org.utils.UserHolder;
import org.springframework.boot.autoconfigure.cache.CacheProperties;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.sql.Struct;
import java.util.Map;
import java.util.concurrent.TimeUnit;

public class RefreshTokenInterceptor implements HandlerInterceptor {

    private StringRedisTemplate stringRedisTemplate;

    public RefreshTokenInterceptor(StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
    }


    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        //从请求头中获取用户登录的token
        String token = request.getHeader("authorization");
        if(StrUtil.isBlank(token)) {
            //直接放行，不做处理
            return true;
        }

        Map<Object, Object> entries = stringRedisTemplate.opsForHash().entries(RedisConstants.LOGIN_USER_KEY + token);
        //entries不会为null,只需要判断是否为空map即可
        if(entries.isEmpty()) {
            //直接放行，不做处理
            return true;
        }
        //将map转成UserDTO
        UserDTO userDTO = BeanUtil.fillBeanWithMap(entries, new UserDTO(), false);
        //将UserDTO存入ThreadMap中
        UserHolder.saveUser(userDTO);
        //刷新token的有效期
        stringRedisTemplate.expire(RedisConstants.LOGIN_USER_KEY + token, RedisConstants.LOGIN_USER_TTL,
                TimeUnit.MINUTES);
        //放行
        return true;
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
        UserHolder.removeUser();
    }
}

登录拦截器

package com.xkj.org.interceptor;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.ObjectUtil;
import cn.hutool.core.util.StrUtil;
import com.xkj.org.dto.UserDTO;
import com.xkj.org.utils.RedisConstants;
import com.xkj.org.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.web.servlet.HandlerInterceptor;

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

public class LoginInterceptor implements HandlerInterceptor {


    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        UserDTO user = UserHolder.getUser();
        if(ObjectUtil.isNull(user)) {
            //未登录,拦截
            response.setStatus(401);
            return false;
        }
        //放行
        return true;
    }

}

拦截器配置类

package com.xkj.org.config;

import com.xkj.org.interceptor.LoginInterceptor;
import com.xkj.org.interceptor.RefreshTokenInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class MvcConfig implements WebMvcConfigurer{

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //添加token刷新拦截器，用户拦截所有请求，获取header中token,获取redis中的用户信息，存入ThreadLocal中，刷新token的有效期
        //设置order,优先执行，值越大优先级越低
        registry.addInterceptor(new RefreshTokenInterceptor(stringRedisTemplate)).addPathPatterns("/**").order(0);

        //添加登录验证拦截器，排除一些不需要拦截的url
        registry.addInterceptor(new LoginInterceptor())
        .excludePathPatterns(
                "/user/code",
                "/user/login",
                "/blog/hot",
                "/shop/**",
                "/shop-type/**",
                "/upload/**",
                "voucher/**"

        ).order(1);
    }
}

ThreadLocal使用

package com.xkj.org.utils;

import com.xkj.org.dto.UserDTO;

public class UserHolder {

    private static final ThreadLocal<UserDTO> t1 = new ThreadLocal<>();

    public static void saveUser(UserDTO userDTO) {
        t1.set(userDTO);
    }

    public static UserDTO getUser() {
        return t1.get();
    }

    public static void removeUser() {
        t1.remove();
    }
}