java把文件字节大小转换成 kb、M、G 等单元

	        
	//文件字节大小转换成 kb、M、G 等单元
	public static String readableFileSize(long size) {
        if (size <= 0) return "0";
        final String[] units = new String[]{"B", "KB", "MB", "GB", "TB"};
        int digitGroups = (int) (Math.log10(size) / Math.log10(1024));
        return new DecimalFormat("#,##0.#").format(size / Math.pow(1024, digitGroups)) + " " + units[digitGroups];
    }