.net core 序列化时将long类型转为string类型

先创建帮助类

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SignalR.Common.Helper
{

    /// <summary>
    /// 将ID转为string类型
    /// </summary>
    public class LongToStringConverter: JsonConverter
    {
        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            JToken jt = JValue.ReadFrom(reader);

            return jt.Values();
        }

        public override bool CanConvert(Type objectType)
        {
            return typeof(System.Int64).Equals(objectType);
        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            serializer.Serialize(writer, value.ToString());
        }
    }

}

在所要转为string的实体上加入

[JsonConverter(typeof(LongToStringConverter))]

         /// <summary>
        /// 主键
        /// </summary>
        [JsonConverter(typeof(LongToStringConverter))]
        [SugarColumn(IsNullable = false, IsPrimaryKey = true)]
        public long ID { get; set; }

最后在startup中注入即可(一定要在startup注册！！！！！！)

　　　　　　//全局配置Json序列化处理
            .AddNewtonsoftJson(options =>
            {
                //忽略循环引用
                options.SerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;
                //不使用驼峰样式的key
                options.SerializerSettings.ContractResolver = new DefaultContractResolver();
                //将long类型转为string
                options.SerializerSettings.Converters.Add(new LongToStringConverter());
                //设置时间格式
                //options.SerializerSettings.DateFormatString = "yyyy-MM-dd";
                //忽略Model中为null的属性
                //options.SerializerSettings.NullValueHandling = NullValueHandling.Ignore;
                //设置本地时间而非UTC时间
                options.SerializerSettings.DateTimeZoneHandling = DateTimeZoneHandling.Local;
            });