"ConnectionStrings": {
    "Default": "Server=.; Database=ABBDb; Trusted_Connection=True;" //本地
  },

#region 获取连接字符串
IConfiguration configuration = new ConfigurationBuilder()
.SetBasePath(Environment.CurrentDirectory)
.AddJsonFile("appsettings.json", true, true)
.AddInMemoryCollection()
.Build();
string sqlConnectionString = configuration["ConnectionStrings:Default"];//Default 
#endregion