Java 解压 zlib

Question

我有一个字节数组，十六进制开始（很大）是这样的：

78 9C 9D 5B 4B 6F A4 38 10 FE 2F 9C 19 89 F2 83 47 1F 77 46 7B DA D3 CE 6A 2F A3 08 91 B4 93 B4 96 40 0B E8 64 A2 28 FF 7D A1 B1 3B 2E C0 ED 72 4F 94 E9 04 EA 61 57 7D F5 32 E4 23 7A AB 5E 55 D9 9C 5E A2 5D 01 10 47 55 B3 EF DA C3 BE 7C A8 0F AA 19 A2 DD D0 9D

它以 0x789c 开始，它是 lzma headers。

我是运行它通过以下方法：

public byte[] decompress(byte[] bytesToDecompress)
    {
        byte[] returnValues = null;

        Inflater inflater = new Inflater();

        int numberOfBytesToDecompress = bytesToDecompress.length;

        inflater.setInput
        (
            bytesToDecompress,
            0,
            numberOfBytesToDecompress
        );

        int bufferSizeInBytes = numberOfBytesToDecompress;

        int numberOfBytesDecompressedSoFar = 0;
        List<Byte> bytesDecompressedSoFar = new ArrayList<Byte>();

        try
        {
            while (inflater.needsInput() == false)
            {
                byte[] bytesDecompressedBuffer = new byte[bufferSizeInBytes];

                int numberOfBytesDecompressedThisTime = inflater.inflate
                (
                    bytesDecompressedBuffer
                );

                numberOfBytesDecompressedSoFar += numberOfBytesDecompressedThisTime;

                for (int b = 0; b < numberOfBytesDecompressedThisTime; b++)
                {
                    bytesDecompressedSoFar.add(bytesDecompressedBuffer[b]);
                }
            }

            returnValues = new byte[bytesDecompressedSoFar.size()];
            for (int b = 0; b < returnValues.length; b++) 
            {
                returnValues[b] = (byte)(bytesDecompressedSoFar.get(b));
            }

        }
        catch (DataFormatException dfe)
        {
            dfe.printStackTrace();
        }

        inflater.end();

        return returnValues;
    }

    public String decompressToString(byte[] bytesToDecompress)
    {   
        byte[] bytesDecompressed = this.decompress
        (
            bytesToDecompress
        );

        String returnValue = null;

        try
        {
            returnValue = new String
            (
                bytesDecompressed,
                0,
                bytesDecompressed.length,
                "UTF-8"
            );  
        }
        catch (UnsupportedEncodingException uee)
        {
            uee.printStackTrace();
        }

        return returnValue;
    }

像这样： System.out.println(decompressToString(jsonDecompressed));

但是我什么也没有打印出来。也没有堆栈跟踪...

怎么会这样？

Answer 1

您的代码已经正确，您只需使用以下问题中的方法将十六进制字符串转换为字节数组：

Convert a string representation of a hex dump to a byte array using Java?

public static byte[] hexStringToByteArray(String s) {
    int len = s.length();
    byte[] data = new byte[len / 2];
    for (int i = 0; i < len; i += 2) {
        data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
                             + Character.digit(s.charAt(i+1), 16));
    }
    return data;
}

然后您可以对十六进制字符串（不带空格）使用之前的方法

 public static void main(String[] args) {
    String strData = "789C9D5B4B6FA43810FE2F9C1989F283471F77467BDAD3CE6A2FA30891B493B496400BE864A228FF7DA1B13B2EC0ED724F94E904EA61577DF532E4237AAB5E55D99C5EA25D01104755B3EFDAC3BE7CA80FAA19A2DDD09D";
    byte[] jsonDecompressed = hexStringToByteArray(strData);
    System.out.println(decompressToString(jsonDecompressed));
}

得到正确的解压值：

{"wave_num":911,"android_client":tr

Java 解压 zlib

Java decompress zlib

java

zlib

lzma