字符串序列化，去空格

String_Serialize_Test.cs

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

namespace UnitTest
{
    public class String_Serialize_Test
    {

        private ITestOutputHelper _testOutputHelper;

        public String_Serialize_Test(ITestOutputHelper testOutputHelper)
        {
            _testOutputHelper = testOutputHelper;
        }

        [Fact]
        public void Serialize()
        {
            var obj = new {
                string1 = "1",
                string2 = "  1  ",
                string3 = (string) null
            };
            var json = JsonConvert.SerializeObject(obj, StringJsonConverter.Instance);

            Assert.Equal(@"{""string1"":""1"",""string2"":""1"",""string3"":null}", json);

        }
    }


    internal sealed class StringJsonConverter : JsonConverter
    {

        public static readonly JsonConverter Instance = new StringJsonConverter();

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            string stringValue = (string) value;

            if (string.IsNullOrEmpty(stringValue) == false)
                stringValue = stringValue.Trim();

            writer.WriteValue(stringValue);
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            throw new NotImplementedException();
        }

        public override bool CanConvert(Type objectType)
        {
            return objectType == typeof(string);
        }

        public override bool CanRead
        {
            get { return false; }
        }
    }
}