@Override
    public String generate(String url) {
        String extension = getExtension(url);
        String name = ProxyCacheUtils.computeMD5(url);
        return TextUtils.isEmpty(extension) ? name : name + "." + extension;
    }
Implementation of {@link FileNameGenerator} that uses MD5 of url as file name
VideoCache/src/main/java/com/yc/videocache/file/Md5FileNameGenerator.java