public class MyJsonOutputFormatter : JsonOutputFormatter{public MyJsonOutputFormatter(JsonSerializerSettings serializerSettings) : base(serializerSettings, ArrayPool<char>.Shared){}public new JsonSerializerSettings SerializerSettings => base.SerializerSettings;protected override JsonWriter CreateJsonWriter(TextWriter writer){if (writer == null){throw new ArgumentNullException(nameof(writer));}var jsonWriter = new NullJsonWriter(writer){ArrayPool = new JsonArrayPool<char>(ArrayPool<char>.Shared),CloseOutput = false,AutoCompleteOnClose = false};return jsonWriter;}}public class NullJsonWriter : JsonTextWriter{public NullJsonWriter(TextWriter textWriter):base(textWriter){}public override void WriteNull(){this.WriteValue(String.Empty);}}

//services.AddMvc().AddJsonOptions(option => {//    //配置大小写问题，默认是首字母小写,该配置根据项目需要更改//    //option.SerializerSettings.ContractResolver = new Newtonsoft.Json.Serialization.DefaultContractResolver();//    //配置序列化时时间格式为时间戳//    //option.SerializerSettings.ContractResolver = new NullToEmptyStringResolver();//    option.SerializerSettings.DateFormatString = "yyyy-MM-dd HH:mm:ss";//});services.AddMvc(config =>{var settings = new JsonSerializerSettings();//设置首字母小写，如果不需要 则改为 DefaultContractResolversettings.ContractResolver = new CamelCasePropertyNamesContractResolver();//统一设置JsonResult中的日期格式    settings.DateFormatString = "yyyy-MM-dd HH:mm:ss";config.OutputFormatters.Insert(0, new MyJsonOutputFormatter(settings));});