GZIPInputStream to String

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I am attempting to convert the gzipped body of a HTTP response to plaintext. I've taken the byte array of this response and converted it to a ByteArrayInputStream. I've then converted this to a GZIPInputStream. I now want to read the GZIPInputStream and store the final decompressed HTTP response body as a plaintext String.

This code will store the final decompressed contents in an OutputStream, but I want to store the contents as a String:

public static int sChunk = 8192;
ByteArrayInputStream bais = new ByteArrayInputStream(responseBytes);
GZIPInputStream gzis = new GZIPInputStream(bais);
byte[] buffer = new byte[sChunk];
int length;
while ((length = gzis.read(buffer, 0, sChunk)) != -1) {
        out.write(buffer, 0, length);
}
gzipinputstream gzip http java
8 Answers

GZipwiki is a file format and a software application used for file compression and decompression. gzip is a single-file/stream lossless data compression utility, where the resulting compressed file generally has the suffix .gz

String(Plain) ➢ Bytes ➤ GZip-Data(Compress) ➦ Bytes ➥ String(Decompress)

String zipData = "Hi Stackoverflow and GitHub";
        
// String to Bytes
byte[] byteStream = zipData.getBytes();
System.out.println("String Data:"+ new String(byteStream, "UTF-8"));

// Bytes to Compressed-Bytes then to String.
byte[] gzipCompress = gzipCompress(byteStream);
String gzipCompressString = new String(gzipCompress, "UTF-8");
System.out.println("GZIP Compressed Data:"+ gzipCompressString);

// Bytes to DeCompressed-Bytes then to String.
byte[] gzipDecompress = gzipDecompress(gzipCompress);
String gzipDecompressString = new String(gzipDecompress, "UTF-8");
System.out.println("GZIP Decompressed Data:"+ gzipDecompressString);

GZip-Bytes(Compress) ➥ File (*.gz) ➥ String(Decompress)

GZip Filename extension .gz and Internet media type is application/gzip.

File textFile = new File("C:/Yash/GZIP/archive.gz.txt");
File zipFile = new File("C:/Yash/GZIP/archive.gz");
org.apache.commons.io.FileUtils.writeByteArrayToFile(textFile, byteStream);
org.apache.commons.io.FileUtils.writeByteArrayToFile(zipFile, gzipCompress);

FileInputStream inStream = new FileInputStream(zipFile);
byte[] fileGZIPBytes = IOUtils.toByteArray(inStream);
byte[] gzipFileDecompress = gzipDecompress(fileGZIPBytes);
System.out.println("GZIPFILE Decompressed Data:"+ new String(gzipFileDecompress, "UTF-8"));

Following functions are used for compression and decompression.

public static byte[] gzipCompress(byte[] uncompressedData) {
    byte[] result = new byte[]{};
    try (
        ByteArrayOutputStream bos = new ByteArrayOutputStream(uncompressedData.length);
        GZIPOutputStream gzipOS = new GZIPOutputStream(bos)
        ) {
        gzipOS.write(uncompressedData);
        gzipOS.close(); // You need to close it before using ByteArrayOutputStream
        result = bos.toByteArray();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return result;
}

public static byte[] gzipDecompress(byte[] compressedData) {
    byte[] result = new byte[]{};
    try (
        ByteArrayInputStream bis = new ByteArrayInputStream(compressedData);
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        GZIPInputStream gzipIS = new GZIPInputStream(bis)
        ) {
        //String gZipString= IOUtils.toString(gzipIS);
        byte[] buffer = new byte[1024];
        int len;
        while ((len = gzipIS.read(buffer)) != -1) {
            bos.write(buffer, 0, len);
        }
        result = bos.toByteArray();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return result;
}
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