读取Json,并替换json中的指定字符

            string jsonfile = @"E:\history.json";//JSON文件路径
            using (System.IO.FileStream file = new FileStream(jsonfile, FileMode.Open, FileAccess.ReadWrite))
            {
                var buffer = new byte[file.Length];//获取用字节表示的流长度
                file.Read(buffer, 0, buffer.Length);//0  字节  1 偏移量  2读取的字节长度
                var jsonTxt = Encoding.UTF8.GetString(buffer);
                JObject o = JObject.Parse(jsonTxt);//获取json对象
                JToken jt = o["Chapter"];//获取Json中的指定字符
                for (int i = 0; i < jt.Count(); i++)//特殊需求 不做理会
                {
                    for (int j = 0; j < jt[i]["article"].Count(); j++)
                    {
                        var arttitle = Convert.ToString(jt[i]["article"][j]["arttitle"]);
                        int num = arttitle.LastIndexOf(" ");
                        if (num != -1)
                        {
                            arttitle = arttitle.Substring(num + 1);
                        }
                        jt[i]["article"][j]["path"] = GetHtmlPath(arttitle, (i + 1) + "-" + (j + 1));
                    }
                }
                var result = o.ToString();
                var newBuffer = Encoding.UTF8.GetBytes(result);
                var index = file.Seek(0, SeekOrigin.Begin);
                file.Write(newBuffer, 0, newBuffer.Count());
            }