代码之家 › 专栏 › 技术社区 › Ihor Deyneka

中的Java Gzip解压缩不正确。净额

gzip compression arrays .net java

Ihor Deyneka · 技术社区 · 7 年前

在文章的底部,我插入了转换为字节数组的十六进制字符串。NET和Java。然后,使用以下方法在Java中解压缩生成的字节数组:

public static Object readObjectFromByte(byte[] bytes)
{
ObjectInputStream oos = null;
try {
  ByteArrayInputStream baos = new ByteArrayInputStream(bytes);
  zis = new GZIPInputStream(baos);
  oos = new ObjectInputStream(zis);
  return oos.readObject();
} catch (Throwable t) { GZIPInputStream zis;
  return null;
} finally {
  try {
    if (oos != null) {
      oos.close();
    }
  } catch (IOException e) {
    e.printStackTrace();
  }
}
}

我在中读了很多关于GZIP问题的文章。NET尝试修复此问题。我使用。NET 4.5,例如,我的上一个解压缩版本是:

Ionic.Zlib.GZipStream.UncompressBuffer(compressedBytes)

这很奇怪,但即使我尝试:

Ionic.Zlib.GZipStream.CompressBuffer(Ionic.Zlib.GZipStream.UncompressBuffer(compressedBytes)).SequenceEquals(compressedBytes)

编辑:

Java代码:

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

public class JavaFiddle
{
public static void main(String[] args)
{
  String hex = "PLEASE_UPDATE"; //update this from the hex constant at the end of the post
  byte[] compressedBytes = hexStringToByteArray(hex);
  byte[] decompressedBytes = (byte[])readObjectFromByte(compressedBytes);
  System.out.println(decompressedBytes.length); //THIS GIVES 3952
}

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;
}

public static Object readObjectFromByte(byte[] bytes)
{
    ObjectInputStream oos = null;
    try {
      ByteArrayInputStream baos = new ByteArrayInputStream(bytes);
      GZIPInputStream zis = new GZIPInputStream(baos);
      oos = new ObjectInputStream(zis);
      return oos.readObject();
    } catch (Throwable t) { GZIPInputStream zis;
      return null;
    } finally {
      try {
        if (oos != null) {
          oos.close();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
}    
}

    private byte[] StringToByteArray(string hex)
    {
        int NumberChars = hex.Length;
        byte[] bytes = new byte[NumberChars / 2];
        for (int i = 0; i < NumberChars; i += 2)
            bytes[i / 2] = Convert.ToByte(hex.Substring(i, 2), 16);
        return bytes;
    }
    ...
    var hex = "PLEASE_UPDATE"; //update this from the hex constant at the end of the post
    var compressedBytes = StringToByteArray(hex);
    var decompressedBytes = Ionic.Zlib.GZipStream.UncompressBuffer(compressedBytes); 
    //decompressedBytes.Length is 3979, Note that this is using one of the external libraries, the same result is for built-in GZipStream in .NET

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

谢谢

1 回复 | 直到 7 年前

Jon Skeet 7 年前

现在我们有了更多的Java代码,我们可以看到问题:在真实数据周围有一个额外的序列化层。这实际上与压缩无关。

下面是一个例子来说明我的意思:

import java.io.*;

public class Test {
    public static void main(String[] args) throws Exception {
        try (ByteArrayOutputStream output = new ByteArrayOutputStream()) {
            try (ObjectOutputStream oos = new ObjectOutputStream(output)) {
                oos.writeObject(new byte[5]);
            }
            byte[] data = output.toByteArray();
            System.out.println(data.length);
        }
    }
}

基本上,以这种方式包装字节数组是很奇怪的,如果可以的话 可能地 更改原始代码,这将是最好的。如果你绝对做不到这一点,它也许请安全地忽略结果数据的前27个字节。