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javazip

How can I convert byte array to ZIP file


I am trying to convert an array of bytes into a ZIP file. I got bytes using the following code:

byte[] originalContentBytes= new Verification().readBytesFromAFile(new File("E://file.zip"));

private byte[] readBytesFromAFile(File file) {
    int start = 0;
    int length = 1024;
    int offset = -1;
    byte[] buffer = new byte[length];
    try {
        //convert the file content into a byte array
        FileInputStream fileInuptStream = new FileInputStream(file);
        BufferedInputStream bufferedInputStream = new BufferedInputStream(
                fileInuptStream);
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

        while ((offset = bufferedInputStream.read(buffer, start, length)) != -1) {
            byteArrayOutputStream.write(buffer, start, offset);
        }

        bufferedInputStream.close();
        byteArrayOutputStream.flush();
        buffer = byteArrayOutputStream.toByteArray();
        byteArrayOutputStream.close();
    } catch (FileNotFoundException fileNotFoundException) {
        fileNotFoundException.printStackTrace();
    } catch (IOException ioException) {
        ioException.printStackTrace();
    }

    return buffer;
}

But my problem now is with converting the byte array back into a ZIP file - how can it be done?

Note : The specified ZIP contains two files.


Solution

  • To get the contents from the bytes you can use

    ZipInputStream zipStream = new ZipInputStream(new ByteArrayInputStream(bytes));
    ZipEntry entry = null;
    while ((entry = zipStream.getNextEntry()) != null) {
    
        String entryName = entry.getName();
    
        FileOutputStream out = new FileOutputStream(entryName);
    
        byte[] byteBuff = new byte[4096];
        int bytesRead = 0;
        while ((bytesRead = zipStream.read(byteBuff)) != -1)
        {
            out.write(byteBuff, 0, bytesRead);
        }
    
        out.close();
        zipStream.closeEntry();
    }
    zipStream.close();