解析springboot整合谷歌开源缓存框架Guava Cache原理

目录

• Guava Cache：谷歌开源缓存框架
• Guava Cache使用
• 使用压测工具Jmeter5.x进行接口压力测试：
  • 压测工具本地快速安装Jmeter5.x
• 新增聚合报告：线程组->添加->监听器->聚合报告（Aggregate Report）

 <!--guava依赖包-->
 <dependency>
 <groupId>com.google.guava</groupId>
 <artifactId>guava</artifactId>
 <version>19.0</version>
 </dependency>

@Component
public class BaseCache {



    private Cache<String,Object> tenMinuteCache = CacheBuilder.newBuilder()

            //设置缓存初始大小，应该合理设置，后续会扩容
            .initialCapacity(10)
            //最大值
            .maximumSize(100)
            //并发数设置
            .concurrencyLevel(5)

            //缓存过期时间，写入后10分钟过期
            .expireAfterWrite(600,TimeUnit.SECONDS)

            //统计缓存命中率
            .recordStats()

            .build();





    private Cache<String,Object> oneHourCache = CacheBuilder.newBuilder()

            //设置缓存初始大小，应该合理设置，后续会扩容
            .initialCapacity(30)
            //最大值
            .maximumSize(100)
            //并发数设置
            .concurrencyLevel(5)

            //缓存过期时间，写入后1小时 过期
            .expireAfterWrite(3600,TimeUnit.SECONDS)

            //统计缓存命中率
            .recordStats()

            .build();





    public Cache<String, Object> getOneHourCache() {
        return oneHourCache;
    }

    public void setOneHourCache(Cache<String, Object> oneHourCache) {
        this.oneHourCache = oneHourCache;
    }

    public Cache<String, Object> getTenMinuteCache() {
        return tenMinuteCache;
    }

    public void setTenMinuteCache(Cache<String, Object> tenMinuteCache) {
        this.tenMinuteCache = tenMinuteCache;
    }
}

/**
 * 缓存key管理类
 */
public class CacheKeyManager {

    /**
     * 首页轮播图缓存key
     */
    public static final String INDEX_BANNER_KEY = "index:banner:list";


    /**
     * 首页视频列表缓存key
     */
    public static final String INDEX_VIDEL_LIST = "index:video:list";


    /**
     * 视频详情缓存key, %s是视频id
     */
    public static final String VIDEO_DETAIL = "video:detail:%s";


}

@Service
public class VideoServiceImpl implements VideoService {

    @Autowired
    private VideoMapper videoMapper;


    @Autowired
    private BaseCache baseCache;


    @Override
    public List<Video> listVideo() {


        try{

          Object cacheObj =  baseCache.getTenMinuteCache().get(CacheKeyManager.INDEX_VIDEL_LIST,()->{

                List<Video> videoList = videoMapper.listVideo();

                return videoList;

            });

          if(cacheObj instanceof List){
              List<Video> videoList = (List<Video>)cacheObj;
              return videoList;
          }

        }catch (Exception e){
            e.printStackTrace();
        }

        //可以返回兜底数据，业务系统降级-》SpringCloud专题课程
        return null;
    }



    @Override
    public List<VideoBanner> listBanner() {

        try{

            Object cacheObj =  baseCache.getTenMinuteCache().get(CacheKeyManager.INDEX_BANNER_KEY, ()->{

                List<VideoBanner> bannerList =  videoMapper.listVideoBanner();

                System.out.println("从数据库里面找轮播图列表");

                return bannerList;

            });

            if(cacheObj instanceof List){
                List<VideoBanner> bannerList = (List<VideoBanner>)cacheObj;
                return bannerList;
            }

        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }




    @Override
    public Video findDetailById(int videoId) {

        //单独构建一个缓存key，每个视频的key是不一样的
        String videoCacheKey = String.format(CacheKeyManager.VIDEO_DETAIL,videoId);

        try{

         Object cacheObject = baseCache.getOneHourCache().get( videoCacheKey, ()->{

                // 需要使用mybaits关联复杂查询
                Video video = videoMapper.findDetailById(videoId);

                return video;

            });

         if(cacheObject instanceof Video){

             Video video = (Video)cacheObject;
             return video;
         }

        }catch (Exception e){
            e.printStackTrace();
        }

        return null;
    }
}