MultipartHelper.java

public class MultipartHelper {

    private final String fileDir;
    private final String outputDir;

    public MultipartHelper(String fileDir, String outputDir) {
        this.fileDir = fileDir;
        String baseDir = BaseApplication.getAppContext().getObbDir() + File.separator + "uploads";
        this.outputDir = baseDir + File.separator;
        File upload = new File(baseDir);
        if (!upload.exists()) {
            upload.mkdir();
        }

    }

    public void split() {
        RandomAccessFile raf = null;
        try {
            raf = new RandomAccessFile(fileDir, "r");
            try {
                long sourceSize = 0;

                sourceSize = raf.length();
                long numSplits = sourceSize / (1024 * 100);
                numSplits += sourceSize % (1024 * 100) > 0 ? 1 : 0;
                long bytesPerSplit = sourceSize / numSplits;
                long remainingBytes = sourceSize % numSplits;

                for (int destIx = 1; destIx <= numSplits; destIx++) {
                    FileOutputStream outputStream = new FileOutputStream(new File(outputDir + "." + destIx));
                    BufferedOutputStream bw = new BufferedOutputStream(outputStream);

                    byte[] buf = new byte[(int) bytesPerSplit];
                    int val = raf.read(buf);
                    if (val != -1) {
                        bw.write(buf);
                    }

                    bw.close();
                }
                if (remainingBytes > 0) {
                    BufferedOutputStream bw = new BufferedOutputStream(new FileOutputStream(new File(outputDir + "." + (numSplits + 1))));
                    readWrite(raf, bw, remainingBytes);
                    bw.close();
                }
                raf.close();

            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                raf.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public File[] getFiles() {
        return new File(outputDir).listFiles();
    }

    public void close() {
        FileUtils.deleteDir(new File(outputDir));
    }

    static void readWrite(RandomAccessFile raf, BufferedOutputStream bw, long numBytes) throws IOException {
        byte[] buf = new byte[(int) numBytes];
        int val = raf.read(buf);
        if (val != -1) {
            bw.write(buf);
        }
    }
}