Spring Batch program to create the fixed size zip file

Question

I have a design issue.I want to create a 10 MB zip files using spring batch. But not sure what value i can select for chunk size. chunk size is predetermined value. lets say i decide that that chunk size is 100. So i read 100 files and try to create a zip file. but what if zip file size reaches 10 MB by just including 99 files. What will happen to the remaining 1 file?

Regards, Raj

Answer 1

I had a similar use case. What I did was to create a service that creates zip files of a limited size (10MB). So for example if I had a 99 files that reaches the 10MB, the service split the zip in two parts: file_to_zip.zip and file_to_zip.z01

public List<File> createSplitFile(List<String> resourcesToZip, String directory, Long maxFileSize, String zipFileName) {
    List<File> splitZipFiles = null;
    try {
        ZipFile zipFile = new ZipFile(directory + zipFileName);
        Iterator<String> iterator = resourcesToZip.iterator();
        List<File> filesToAdd = new ArrayList();
        while (iterator.hasNext()) {
            File file = new File(iterator.next());
            if (file.exists()) {
                filesToAdd.add(file);
            }
        }

        ZipParameters parameters = new ZipParameters();
        parameters.setCompressionMethod(CompressionMethod.DEFLATE);
        parameters.setCompressionLevel(CompressionLevel.NORMAL);

        zipFile.createSplitZipFile(filesToAdd, parameters, true, maxFileSize);
        splitZipFiles = zipFile.getSplitZipFiles();
    } catch (ZipException e) {
        LOG.error("Exception trying to compress statement file '{}'", e.getMessage());
    }
    return splitZipFiles;
}