1. 添加引用
   using Newtonsoft.Json.Linq;

2. 遍历json对象，转为DataTable

JObject jo = JObject.Parse(json);
if (jo.Property("data") == null)
     return "json解析错误";

//获取数据
JArray data = (JArray)jo["data"];
if (data.Count == 0)
     return "数据条数为0";
            
//数据主体
try
{
    DataTable dt = new DataTable();
    JObject job = (JObject)data[0];
    foreach (var v in job)
    {
        dt.Columns.Add(v.Key);
    }
    for (int i = 0; i < data.Count; i++)
    {
         JObject data1 = (JObject)data[i];
         DataRow dr = dt.NewRow();
         foreach (var v in data1)
         {
            dr[v.Key] = (v.Value.ToString() == "" ? null :v.Value.ToString());
         }
         dt.Rows.Add(dr);
    }
   //批量插入数据
string str_sql_conn = System.Configuration.ConfigurationManager.AppSettings["SqlConnString"].ToString();
//////略……
}catch (Exception e)
{
    msg = e.Message.ToString();
}
return msg;