[英]Gzip compression and decompression without any encoding
I want to decompress a string in java which was gzip compressed in python. 我想在java中解压缩一个字符串,该字符串在python中被gzip压缩。
Normally, I use base64 encoding on compressed string in python and then decode that compressed string before performing decompression in java. 通常,我在python中对压缩字符串使用base64编码,然后在Java中执行解压缩之前解码该压缩字符串。 This works fine while using base64 encoding.
使用base64编码时,这可以正常工作。
But is there a way to decompress a string in java which was gzip compressed in python without using base64 encoding. 但是有没有一种方法可以解压缩java中的字符串,而该字符串在python中是gzip压缩的,而无需使用base64编码。
Actually, I want to http post the compressed binary data to a server where the binary data gets decompressed. 实际上,我想将压缩后的二进制数据http发布到服务器上,在该服务器中解压缩二进制数据。 Here compression and http post in done in python and server side is java.
在python和服务器端完成的压缩和http发布是java。
I tried this code without base64 encode in python and read that in java using buffered reader and then converted that read compressed string into byte[] using getBytes() which is given to GZIPInputStream for decompression. 我尝试了在python中没有base64编码的代码,并使用缓冲的读取器在java中读取了代码,然后使用getBytes()将读取的压缩字符串转换为byte [],该字节被提供给GZIPInputStream进行解压缩。 But this throws an exception as:
但这引发了一个异常:
java.io.IOException: Not in GZIP format at
java.util.zip.GZIPInputStream.readHeader(GZIPInputStream.java:154)
at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:75)
at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:85)
at GZipFile.gunzipIt(GZipFile.java:58)
at GZipFile.main(GZipFile.java:42)
Please give me a solution to perform compression and decompression without any encoding. 请给我一个无需任何编码即可执行压缩和解压缩的解决方案。 Is there a way to send binary data in http post in python?
有没有办法在python的http post中发送二进制数据?
This is the compression code in python: 这是python中的压缩代码:
import StringIO
import gzip
import base64
import os
m='hello'+'\r\n'+'world'
out = StringIO.StringIO()
with gzip.GzipFile(fileobj=out, mode="wb") as f:
f.write(m)
f=open('comp_dump','wb')
f.write(base64.b64encode(out.getvalue()))
f.close()
This is the decompression code in java: 这是java中的解压缩代码:
//$Id$
import java.io.*;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import javax.xml.bind.DatatypeConverter;
import java.util.Arrays;
public class GZipFile
{
public static String readCompressedData()throws Exception
{
String compressedStr ="";
String nextLine;
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream("comp_dump")));
try
{
while((nextLine=reader.readLine())!=null)
{
compressedStr += nextLine;
}
}
finally
{
reader.close();
}
return compressedStr;
}
public static void main( String[] args ) throws Exception
{
GZipFile gZip = new GZipFile();
byte[] contentInBytes = DatatypeConverter.parseBase64Binary(readCompressedData());
String decomp = gZip.gunzipIt(contentInBytes);
System.out.println(decomp);
}
/**
* GunZip it
*/
public static String gunzipIt(final byte[] compressed){
byte[] buffer = new byte[1024];
StringBuilder decomp = new StringBuilder() ;
try{
GZIPInputStream gzis = new GZIPInputStream(new ByteArrayInputStream(compressed));
int len;
while ((len = gzis.read(buffer)) > 0) {
decomp.append(new String(buffer, 0, len));
}
gzis.close();
}catch(IOException ex){
ex.printStackTrace();
}
return decomp.toString();
}
} }
Not every byte[] can be converted to a string, and the conversion back could give other bytes.
并非每个byte []都可以转换为字符串,并且转换回来可以提供其他字节。
Please define encoding explicitly when compress and do the same when decompress. 请在压缩时显式定义编码,在解压缩时进行相同的定义。 Otherwise your
OS
, JVM
etc... will do it for you. 否则,您的
OS
, JVM
等将为您完成此任务。 And probably will mess it up. 可能会弄乱它。
For example: on my Linux machine: 例如:在我的Linux机器上:
Python 蟒蛇
import sys
print sys.getdefaultencoding()
>> ascii
Java Java的
System.out.println(Charset.defaultCharset());
>> UTF-8
Related answer: https://stackoverflow.com/a/14467099/3014866 相关答案: https : //stackoverflow.com/a/14467099/3014866
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