/**
 * 使用gzip壓縮字符串
 */
public static String compress(String str) {
    if (str == null || str.length() == 0) {
        return str;
    }
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    GZIPOutputStream gzip = null;
    try {
        gzip = new GZIPOutputStream(out);
        gzip.write(str.getBytes());
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (gzip != null) {
            try {
                gzip.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    return new sun.misc.BASE64Encoder().encode(out.toByteArray());
}
 
/**
 * 使用gzip解壓縮
 */
public static String uncompress(String compressedStr) {
    if (compressedStr == null || compressedStr.length() == 0) {
        return compressedStr;
    }
 
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    ByteArrayInputStream in = null;
    GZIPInputStream ginzip = null;
    byte[] compressed = null;
    String decompressed = null;
    try {
        compressed = new sun.misc.BASE64Decoder().decodeBuffer(compressedStr);
        in = new ByteArrayInputStream(compressed);
        ginzip = new GZIPInputStream(in);
        byte[] buffer = new byte[1024];
        int offset = -1;
        while ((offset = ginzip.read(buffer)) != -1) {
            out.write(buffer, 0, offset);
        }
        decompressed = out.toString();
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (ginzip != null) {
            try {
                ginzip.close();
            } catch (IOException e) {
            }
        }
        if (in != null) {
            try {
                in.close();
            } catch (IOException e) {
            }
        }
        if (out != null) {
            try {
                out.close();
            } catch (IOException e) {
            }
        }
    }
    return decompressed;
}

        !-- https://mvnrepository.com/artifact/com.github.luben/zstd-jni -->
        dependency>
            groupId>com.github.luben/groupId>
            artifactId>zstd-jni/artifactId>
            version>1.4.5-6/version>
        /dependency>

public class ConfigCacheUtil {
    private static ZstdDictCompress compressDict;
    private static ZstdDictDecompress decompressDict;
    private static final Integer LEVEL = 5;
    public static void train() throws IOException {
        // 初始化詞典對象
        String dictContent = FileUtils.readFileToString(new File("/Users/yangguang/vscode/text/cache.json"),
            StandardCharsets.UTF_8);
        byte[] dictBytes = dictContent.getBytes(StandardCharsets.UTF_8);
        compressDict = new ZstdDictCompress(dictBytes, LEVEL);
        decompressDict = new ZstdDictDecompress(dictBytes);
    }
    public static void main(String[] args) throws IOException {
        String read = FileUtils.readFileToString(new File("/Users/yangguang/vscode/text/cache.json"));
        ConfigCacheUtil.testGzip(read);
        System.out.println("");
        ConfigCacheUtil.test(read.getBytes());
        System.out.println("");
        ConfigCacheUtil.testByTrain(read.getBytes());
    }
    public static void testGzip(String str) {
        logger.info("初始數據: {}", str.length());
        // 壓縮數據
        long compressBeginTime = System.currentTimeMillis();
        String compressed = ConfigCacheUtil.compress(str);
        long compressEndTime = System.currentTimeMillis();
        logger.info("壓縮耗時: {}", compressEndTime - compressBeginTime);
        logger.info("數據大小: {}", compressed.length());
        // 解壓數據
        long decompressBeginTime = System.currentTimeMillis();
        // 第 3 個參數不能小于解壓后的字節數組的大小
        String decompressed = ConfigCacheUtil.uncompress(compressed);
        long decompressEndTime = System.currentTimeMillis();
        logger.info("解壓耗時: {}", decompressEndTime - decompressBeginTime);
        logger.info("數據大小: {}", decompressed.length());
    }
    
    public static void test(byte[] bytes) {
        logger.info("初始數據: {}", bytes.length);
        // 壓縮數據
        long compressBeginTime = System.currentTimeMillis();
        byte[] compressed = Zstd.compress(bytes);
        long compressEndTime = System.currentTimeMillis();
        logger.info("壓縮耗時: {}", compressEndTime - compressBeginTime);
        logger.info("數據大小: {}", compressed.length);
        // 解壓數據
        long decompressBeginTime = System.currentTimeMillis();
        // 第 3 個參數不能小于解壓后的字節數組的大小
        byte[] decompressed = Zstd.decompress(compressed, 20 * 1024 * 1024 * 8);
        long decompressEndTime = System.currentTimeMillis();
        logger.info("解壓耗時: {}", decompressEndTime - decompressBeginTime);
        logger.info("數據大小: {}", decompressed.length);
    }
    public static void testByTrain(byte[] bytes) throws IOException {
        ConfigCacheUtil.train();
        logger.info("初始數據: {}", bytes.length);
        // 壓縮數據
        long compressBeginTime = System.currentTimeMillis();
        byte[] compressed = Zstd.compress(bytes, compressDict);
        long compressEndTime = System.currentTimeMillis();
        logger.info("壓縮耗時: {}", compressEndTime - compressBeginTime);
        logger.info("數據大小: {}", compressed.length);
        // 解壓數據
        long decompressBeginTime = System.currentTimeMillis();
        // 第 3 個參數不能小于解壓后的字節數組的大小
        byte[] decompressed = Zstd.decompress(compressed, decompressDict, 20 * 1024 * 1024 * 8);
        long decompressEndTime = System.currentTimeMillis();
        logger.info("解壓耗時: {}", decompressEndTime - decompressBeginTime);
        logger.info("數據大小: {}", decompressed.length);
        compressDict.toString();
    }
}