缓存优化

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image-20200909163600765

caffeine

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// 帖子列表缓存
private LoadingCache<String, List<DiscussPost>> postListCache;

// 帖子总数缓存
private LoadingCache<Integer, Integer> postRowsCache;

@PostConstruct
public void init() {
    // 初始化帖子列表缓存
    postListCache = Caffeine.newBuilder()
            .maximumSize(maxSize)
            .expireAfterWrite(expireSeconds, TimeUnit.SECONDS)
            .build(new CacheLoader<String, List<DiscussPost>>() {
                @Nullable
                @Override
                public List<DiscussPost> load(@NonNull String key) throws Exception {
                    if (key == null || key.length() == 0) {
                        throw new IllegalArgumentException("参数错误!");
                    }

                    String[] params = key.split(":");
                    if (params == null || params.length != 2) {
                        throw new IllegalArgumentException("参数错误!");
                    }

                    int offset = Integer.valueOf(params[0]);
                    int limit = Integer.valueOf(params[1]);

                    // 二级缓存: Redis -> mysql

                    logger.debug("load post list from DB.");
                    return discussPostMapper.selectDiscussPosts(0, offset, limit, 1);
                }
            });
    // 初始化帖子总数缓存
    postRowsCache = Caffeine.newBuilder()
            .maximumSize(maxSize)
            .expireAfterWrite(expireSeconds, TimeUnit.SECONDS)
            .build(new CacheLoader<Integer, Integer>() {
                @Nullable
                @Override
                public Integer load(@NonNull Integer key) throws Exception {
                    logger.debug("load post rows from DB.");
                    return discussPostMapper.selectDiscussPostRows(key);
                }
            });
}