/**
     * 字节转换
     * 
     * @param size 字节大小
     * @return 转换后值
     */
    public String convertFileSize(long size)
    {
        long kb = 1024;
        long mb = kb * 1024;
        long gb = mb * 1024;
        if (size >= gb)
        {
            return String.format("%.1f GB", (float) size / gb);
        }
        else if (size >= mb)
        {
            float f = (float) size / mb;
            return String.format(f > 100 ? "%.0f MB" : "%.1f MB", f);
        }
        else if (size >= kb)
        {
            float f = (float) size / kb;
            return String.format(f > 100 ? "%.0f KB" : "%.1f KB", f);
        }
        else
        {
            return String.format("%d B", size);
        }
    }