public void ConfigureServices(IServiceCollection services){

    services.AddMvc().AddJsonOptions(option=>{

    //配置大小写问题，默认是首字母小写

    option.SerializerSettings.ContractResolver = new Newtonsoft.Json.Serialization.DefaultContractResolver();

   //配置序列化时时间格式为yyyy-MM-dd HH:mm:ss

    option.SerializerSettings.DateFormatString = "yyyy-MM-dd HH:mm:ss";

   })

}