@Override
public void init(ServletConfig config) throws ServletException {
super.init(config);
mapper.setSerializationInclusion(JsonSerialize.Inclusion.NON_NULL);
volumeManager = new VolumeManagerImpl();
initVolumes();
commandFactory = new CommandFactoryImpl(volumeManager);
DiskFileItemFactory factory = new DiskFileItemFactory();
fileUpload = new ServletFileUpload(factory);
fileUpload.setFileSizeMax(this.config.getUploadMaxSize());