Gerar .zip contendo todos os arquivos de um List em um único .zip

/**
	 * Metodo que compacta o arquivo csv gerado
	 * 
	 * @param fileToExport
	 * @return {@String} fileName
	 * @throws Exception
	 * @author paulo.leite
	 */
	private String zipFileToFinalize(File toGroupFiles, File... filesToExport) throws Exception {

		byte[] buffer = new byte[18024];

		// Nome do arquivo ZIP
		String rootPath = fileToExport.getParent();
		if (rootPath.lastIndexOf("/") != rootPath.length() - 1) {
			rootPath  += "/";
		}
		
		String zipFileName = rootPath + toGroupFiles.getName().replace(".csv", ".zip"); //se for csv usa mesmo nome.zip

               
		try {
			ZipOutputStream out = new ZipOutputStream(new FileOutputStream(zipFileName));

			// Ajusta modo de compressão
			out.setLevel(Deflater.BEST_COMPRESSION);

                        for(File fileToAdd : filesToExport) {

			  FileInputStream in = new FileInputStream(fileToAdd);
                           
			  // Add ZIP entry to output stream.
			  out.putNextEntry(new ZipEntry(fileToAdd.getName()));
			  // Transfer bytes from the current file to the ZIP file
			  int len;
			  while ((len = in.read(buffer)) > 0) {
				out.write(buffer, 0, len);
			  }
			  // Fecha o Entry
			  out.closeEntry();
			  // Close the current file input stream
			  in.close();
                      }  
			// Close the ZipOutPutStream
			out.close();

		} catch (IllegalArgumentException iae) {

			throw new AdminExportDataException(iae);

		} catch (Exception e) {

			throw new AdminExportDataException(e);

		}
		
		return zipFileName;

	}