LoadingCache简单实例，使用google缓存机制缓存每

使用LoadingCache缓存每天数据库第一条数据并保存

 private LoadingCache<String, Integer> minId = CacheBuilder.newBuilder().expireAfterWrite(1L, TimeUnit.DAYS).build(new CacheLoader<String, Integer>() {
    @Override
    public Integer load(String mixdate) throws Exception {
      Date date = LocalDate.parse(StringUtils.substringAfter(s, "@")).toDate();
      // 在本地没有缓存的时候会调用该方法进行加载，将获取的值进行缓存并返回结果
      if (ACTIVE_COUNTER.startsWith(mixdate)) {
        LoginLog loginLog = loginLogRepository.getTopByLoginTimeBeforeOrderByIdDesc(date);
        if (loginLog != null) {
          return loginLog.getId();
        }
      } else if (PLAYED_COUNTER.startsWith(mixdate)) {
        ViewHistory viewHistory = viewHistoryRepository.getTopByViewtimeBeforeOrderByIdDesc(date);
        if (viewHistory != null) {
          return viewHistory.getId();
        }
      } else if (ADCLICK_COUNTER.startsWith(mixdate)) {
        AdvClickHistory advClickHistory = advClickHistoryRepository.getTopByCreateTimeBeforeOrderByIdDesc(date);
        if (advClickHistory != null) {
          return advClickHistory.getId();
        }
      }
      return 0;
    }
  });

minId.getUnchecked(StringUtils.join(type, "@", date));

在这里取出当天的数据key，因为每天date都不一样，所以会获取当天的第一条数据，并缓存起来！