先把代码贴上，有时间再整理

namespace MvcApplication1.Controllers{    public class TestController : ApiController    {        [HttpGet]        public TimeClass TE()        {            return new TimeClass { Now=DateTime.Now };        }    }    public class TimeClass    {        [JsonConverter(typeof(SimpleDateConverter))]        public DateTime Now { get; set; }    }    public class SimpleDateConverter : DateTimeConverterBase    {        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)        {            DateTime date = new DateTime();            DateTime.TryParse((string)reader.Value, out date);            return date;        }        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)        {            writer.WriteValue(((DateTime)value).ToString("yyyy-MM-dd HH:mm:ss"));        }    }}