代码实例：

string json_data = "假装json数据";

// 压缩 json 数据
string json_data = JsonCompress(json_data);

封装代码：

        private string JsonCompress(string json)
        {
            StringBuilder sb = new StringBuilder();
            using (StringReader reader = new StringReader(json))
            {
                int ch = -1;
                int lastch = -1;
                bool isQuoteStart = false;
                while ((ch = reader.Read()) > -1)
                {
                    if ((char)lastch != '\\' && (char)ch == '\"')
                    {
                        if (!isQuoteStart)
                        {
                            isQuoteStart = true;
                        }
                        else
                        {
                            isQuoteStart = false;
                        }
                    }
                    if (!Char.IsWhiteSpace((char)ch) || isQuoteStart)
                    {
                        sb.Append((char)ch);
                    }
                    lastch = ch;
                }
            }
            return sb.ToString();
        }