public String getCacheInfo() {
        // lock before reading cache.
        lock.readLock().lock();
        String result = null;
        try {
            result = FileUtils.readFileToString(this.file, StandardCharsets.UTF_8);
        } catch (IOException ex) {
            LOGGER.error("exception on reading {}", this.file, ex);
        } finally {
            lock.readLock().unlock();
        }
        return result;
    }
file with cache time in ms
@param file file
@param cacheTime cache time.
inlong-agent/agent-common/src/main/java/org/apache/inlong/agent/cache/LocalFileCache.java