LZ4与放气压缩管柱相比速度不快

Question

I tried to use LZ4 compression to compress a string object.But the result are not in favour to LZ4 Here is the program i tried

public class CompressionDemo {

    public static byte[] compressGZIP(String data) throws IOException {
        long start = System.nanoTime ();
        ByteArrayOutputStream bos = new ByteArrayOutputStream(data.length());
        GZIPOutputStream gzip = new GZIPOutputStream(bos);
        gzip.write(data.getBytes());
        gzip.close();
        byte[] compressed = bos.toByteArray();
        bos.close();
        System.out.println(System.nanoTime()-start);
        return compressed;
    }

    public static byte[] compressLZ4(String data) throws IOException {
        long start = System.nanoTime ();
        LZ4Factory factory = LZ4Factory.fastestJavaInstance();
        LZ4Compressor compressor = factory.highCompressor();
        byte[] result = compressor.compress(data.getBytes());
        System.out.println(System.nanoTime()-start);
        return result;

    }

    public static byte[] compressDeflater(String stringToCompress) {
        long start = System.nanoTime ();
        byte[] returnValues = null;
        try {
            Deflater deflater = new Deflater(Deflater.BEST_COMPRESSION);
            deflater.setInput(stringToCompress.getBytes("UTF-8"));
            deflater.finish();
            byte[] bytesCompressed = new byte[Short.MAX_VALUE];
            int numberOfBytesAfterCompression = deflater.deflate(bytesCompressed);
            returnValues = new byte[numberOfBytesAfterCompression];
            System.arraycopy(bytesCompressed, 0, returnValues, 0, numberOfBytesAfterCompression);
        } catch (Exception uee) {
            uee.printStackTrace();
        }
        System.out.println(System.nanoTime()-start);
        return returnValues;
    }



    public static void main(String[] args) throws IOException, DataFormatException {
        System.out
                .println("..it’s usually most beneficial to compress anyway, and determine which payload (the compressed or the uncompressed one) has the smallest size and include a small token to indicate whether decompression is required."
                        .getBytes().length);
        byte[] arr = compressLZ4("..it’s usually most beneficial to compress anyway, and determine which payload (the compressed or the uncompressed one) has the smallest size and include a small token to indicate whether decompression is required.");
        System.out.println(arr.length);
    }
}

I have collected statics as above.But LZ4 is not that fast as stated Please let me where am i doing wrong.

Answer 1

Your results are meaningless because the size before compression is too small. You are trying to measure the compression of a few thousand bytes at speeds over 100MB/s. The measurement is lost in the time taken by the JVM to warm up. Try again with an input file of several MBs. You should get numbers in line with my LZ4 implementation here: https://github.com/flanglet/kanzi/wiki/Compression-examples .