In Java: How to zip file from byte[] array?

You can use Java's java.util.zip.ZipOutputStream to create a zip file in memory. For example:

public static byte[] zipBytes(String filename, byte[] input) throws IOException {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    ZipOutputStream zos = new ZipOutputStream(baos);
    ZipEntry entry = new ZipEntry(filename);
    entry.setSize(input.length);
    zos.putNextEntry(entry);
    zos.write(input);
    zos.closeEntry();
    zos.close();
    return baos.toByteArray();
}

I have the same problem but i needed a many files in a zip.

 protected byte[] listBytesToZip(Map<String, byte[]> mapReporte) throws IOException {
    String extension = ".pdf";
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    ZipOutputStream zos = new ZipOutputStream(baos);
    for (Entry<String, byte[]> reporte : mapReporte.entrySet()) {
        ZipEntry entry = new ZipEntry(reporte.getKey() + extension);
        entry.setSize(reporte.getValue().length);
        zos.putNextEntry(entry);
        zos.write(reporte.getValue());
    }
    zos.closeEntry();
    zos.close();
    return baos.toByteArray();
}

Maybe the java.util.zip package might help you

Since you're asking about how to convert from byte array I think (not tested) you can use the ByteArrayInputStream method

int     read(byte[] b, int off, int len)
          Reads up to len bytes of data into an array of bytes from this input stream.

that you will feed to

ZipInputStream  This class implements an input stream filter for reading files in the ZIP file format.

You have to use a ZipOutputStream for that.

http://java.sun.com/javase/6/docs/api/java/util/zip/ZipOutputStream.html

ByteArrayInputStream bais = new ByteArrayInputStream(retByte);
                
ZipInputStream zis = new ZipInputStream(bais);
           
zis.getNextEntry();

Scanner sc = new Scanner(zis);
while (sc.hasNextLine()) {
    System.out.println("-->:" +sc.nextLine());
}

zis.closeEntry();
zis.close();

   byte[] createReport() {
    try {
     ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
     ZipArchiveOutputStream zipOutputStream = new 
     ZipArchiveOutputStream(byteArrayOutputStream);
     
     zipOutputStream.setMethod(ZipArchiveOutputStream.STORED);
     zipOutputStream.setEncoding(ENCODING);

     String text= "text";
     byte[] textBytes = text.getBytes(StandardCharsets.UTF_8);

     ArchiveEntry zipEntryReportObject = newStoredEntry("file.txt", textBytes);
     zipOutputStream.putArchiveEntry(zipEntryReportObject);
     zipOutputStream.write(textBytes);

     zipOutputStream.closeArchiveEntry();
     zipOutputStream.close();
    
     return byteArrayOutputStream.toByteArray();
     } catch (IOException e) {
       return null;
    }

and

ArchiveEntry newStoredEntry(String name, byte[] data) {
    ZipArchiveEntry zipEntry = new ZipArchiveEntry(name);
    zipEntry.setSize(data.length);
    zipEntry.setCompressedSize(zipEntry.getSize());
    CRC32 crc32 = new CRC32();
    crc32.update(data);
    zipEntry.setCrc(crc32.getValue());
    return zipEntry;
  }

public static void createZip(byte[] data) throws ZipException {
    ZipInputStream zipStream = new ZipInputStream(new ByteArrayInputStream(data));
    ZipParameters parameters = new ZipParameters();
    parameters.setFileNameInZip("bank.zip");
    new ZipFile("F:\\ssd\\bank.zip").addStream(new ByteArrayInputStream(data), parameters);
}