How can I convert byte array to ZIP file

Question

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.

What exactly do you want? Do you want to write the bytes back to disk into a zip file? Or do you want to read the contents? The bytes how you read them are not decoded yet. — morja, Dec 03 '11 at 10:47
@ morja -> yes i want to write the bytes back to disk in the form of zip file. — Mohan, Dec 03 '11 at 10:52
Well, but then just write the bytes back to disk with a FileOutputStream and name the file .zip. Dont you want to write the extracted files? — morja, Dec 03 '11 at 10:56
@morja -> yes i tried using FileOutputStream but i can't get the exact zip file. — Mohan, Dec 03 '11 at 11:01
I still dont fully understand what you want to do... can you update your question and describe step by step or with an example what you want to achieve? — morja, Dec 03 '11 at 11:24

score 31 · Accepted Answer · edited Feb 22 '13 at 03:53

31

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();

edited Feb 22 '13 at 03:53

ramjaane

13
6

answered Dec 03 '11 at 10:51

morja

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1

ya this helps me to get the entry name which is present inside the zip file. Using this we can only read the content. but how can we store it to disk. – Mohan Dec 03 '11 at 11:03
1

You can read the bytes from the zipStream and then write it with a FileOutputStream. Or directly write it out again. See my update. – morja Dec 03 '11 at 11:32

score 8 · Answer 2 · answered Dec 03 '11 at 10:52

8

You probably are looking for code like this:

ZipInputStream z = new ZipInputStream(new ByteArrayInputStream(buffer))

now you can get the zip file contents via getNextEntry()

answered Dec 03 '11 at 10:52

Has QUIT--Anony-Mousse

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score 0 · Answer 3 · answered Aug 04 '21 at 10:11

Here is a helper method

private fun getZipData(): ByteArray {
    val zipFile: File = getTempZipFile() // Return a zip File

    val encoded = Files.readAllBytes(Paths.get(zipFile.absolutePath))
    zipFile.delete() // If you wish to delete the zip file

    return encoded
}

How can I convert byte array to ZIP file

3 Answers3

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