How to let user download zip file using vaadin file downloader

Question

I've followed this topic and it perfectly works. Here's the function to create resource for file downloader

 private StreamResource createResource() {
    return new StreamResource(new StreamSource() {
        @Override
        public InputStream getStream() {
            String text = "My image";

            BufferedImage bi = new BufferedImage(100, 30, BufferedImage.TYPE_3BYTE_BGR);
            bi.getGraphics().drawChars(text.toCharArray(), 0, text.length(), 10, 20);

            try {
                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                ImageIO.write(bi, "png", bos);
                return new ByteArrayInputStream(bos.toByteArray());
            } catch (IOException e) {
                e.printStackTrace();
                return null;
            }

        }
    }, "myImage.png");
}

but i don't know how to make it create a resource of zip file. Do i need to create many resources?. Thank you

If you want to make a ZIP file, follow [this](http://www.oracle.com/technetwork/articles/java/compress-1565076.html) tutorial at section "Compressing and Archiving Data in a ZIP File". — Steffen Harbich, Jul 25 '16 at 07:27

score 1 · Accepted Answer · answered Jul 28 '16 at 15:15

Here's the solution that i figured out myself

private StreamResource createZipResource()
{ 
    return new StreamResource(new StreamSource()
    { 
        @Override
        public InputStream getStream()
        {
            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

            try
            {
                ZipOutputStream out = new ZipOutputStream(byteArrayOutputStream);

                for (int i = 0; i < listData.size(); i++)
                {
                    if (listData.get(i).contains(".txt"))
                    { 
                        out.putNextEntry(new ZipEntry(listData.get(i) + ".txt"));
                    }
                    else
                    {
                        out.write(listData.get(i).getBytes());                            
                    } 
                }
                out.close();
                return new ByteArrayInputStream(byteArrayOutputStream.toByteArray()); 
            } 
            catch (IOException e)
            {
                System.out.println("Problem writing ZIP file: " + e);
            }
            return null; 
        }
    },"Filename.zip"); 
}

How to let user download zip file using vaadin file downloader

1 Answers1