缓存一致性问题

之前在文章列表读取，最新文章等接口的时候我们加了缓存，但是加了缓存会有一些问题，当我们修改或者用户浏览了文章，那么最新的修改和文章的浏览数量无法及时的更新，那么应该怎么做呢？

这里我们采用RocketMQ来解决这个问题。

安装rocketMQ

#docker 拉取
docker pull foxiswho/rocketmq:4.8.0
#启动nameserver
docker run -d -v /usr/local/rocketmq/logs:/opt/docker/rocketmq/logs \
      --name rmqnamesrv \
      -e "JAVA_OPT_EXT=-Xms512M -Xmx512M -Xmn128m" \
      -p 9876:9876 \
      foxiswho/rocketmq:4.8.0 \
      sh mqnamesrv
#broker.conf
brokerIP1=192.168.200.100
namesrvAddr=192.168.200.100:9876
brokerName=broker_all
#启动broker
docker run -d  -v /opt/docker/rocketmq/logs:/usr/local/rocketmq/logs -v /opt/docker/rocketmq/store:/usr/local/rocketmq/store \
      -v /opt/docker/rocketmq/conf:/usr/local/rocketmq/conf \
      --name rmqbroker \
      -e "NAMESRV_ADDR=192.168.200.100:9876" \
      -e "JAVA_OPT_EXT=-Xms512M -Xmx512M -Xmn128m" \
      -p 10911:10911 -p 10912:10912 -p 10909:10909 \
      foxiswho/rocketmq:4.8.0 \
      sh mqbroker -c /usr/local/rocketmq/conf/broker.conf
#rocketmq-console-ng
docker pull styletang/rocketmq-console-ng

docker run --name rmqconsole --link rmqnamesrv:rmqnamesrv \
-e "JAVA_OPTS=-Drocketmq.namesrv.addr=192.168.200.100:9876 -Dcom.rocketmq.sendMessageWithVIPChannel=false" \
-p 8180:8080 -t styletang/rocketmq-console-ng

#启动访问 http://192.168.200.100:8180/

集成

        <dependency>
            <groupId>org.apache.rocketmq</groupId>
            <artifactId>rocketmq-spring-boot-starter</artifactId>
            <version>2.2.0</version>
        </dependency>

添加对应的配置：

#rocketmq配置
rocketmq.name-server=192.168.200.100:9876
rocketmq.producer.group=blog_group

代码：

   if (isEdit){
            //发送一条消息给rocketmq 当前文章更新了，更新一下缓存吧
            ArticleMessage articleMessage = new ArticleMessage();
            articleMessage.setArticleId(article.getId());
            rocketMQTemplate.convertAndSend("blog-update-article",articleMessage);
        }

package com.mszlu.blog.service.mq;

import com.alibaba.fastjson.JSON;
import com.mszlu.blog.service.ArticleService;
import com.mszlu.blog.vo.ArticleMessage;
import com.mszlu.blog.vo.Result;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.rocketmq.spring.annotation.RocketMQMessageListener;
import org.apache.rocketmq.spring.core.RocketMQListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.Duration;
import java.util.Set;

/**
 * @author B站：码神之路
 */
@Slf4j
@Component
@RocketMQMessageListener(topic = "blog-update-article",consumerGroup = "blog-update-article-group")
public class ArticleListener implements RocketMQListener<ArticleMessage> {

    @Autowired
    private ArticleService articleService;
    @Autowired
    private StringRedisTemplate redisTemplate;

    @Override
    public void onMessage(ArticleMessage message) {
        log.info("收到的消息:{}",message);
        //做什么了，更新缓存
        //1. 更新查看文章详情的缓存
        Long articleId = message.getArticleId();
        String params = DigestUtils.md5Hex(articleId.toString());
        String redisKey = "view_article::ArticleController::findArticleById::"+params;
        Result articleResult = articleService.findArticleById(articleId);
        redisTemplate.opsForValue().set(redisKey, JSON.toJSONString(articleResult), Duration.ofMillis(5 * 60 * 1000));
        log.info("更新了缓存:{}",redisKey);
        //2. 文章列表的缓存 不知道参数,解决办法 直接删除缓存
        Set<String> keys = redisTemplate.keys("listArticle*");
        keys.forEach(s -> {
            redisTemplate.delete(s);
            log.info("删除了文章列表的缓存:{}",s);
        });

    }
}