使用JSON.Net（Newtonsoft.Json）作為ASP.Net MVC的json序列化和還原序列化工具

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ASP.Net MVC預設的JSON序列化使用的是微軟自己的JavaScriptSerializer。效能低不說，最讓人受不了的是Dictionary<,>和Hashtable類型居然對應的json是[{"Key":"a","Value":1}]而不是{"a":1}。真是奇葩到家了，跟前端根本沒法整合！

決定還是用JSON.Net來做吧！查了各種資料，網上的要麼代碼太複雜，要麼沒法完全實現。又在ILSpy分析了MVC源碼，然後調試了半天，終於有了初步的解決辦法：

1、還原序列化，首先建立下面的類：

 1 using System; 2 using System.Globalization; 3 using System.IO; 4 using System.Web.Mvc; 5 using Newtonsoft.Json.Linq; 6  7 namespace HZ 8 { 9     public class JsonNetValueProviderFactory : ValueProviderFactory10     {11         public override IValueProvider GetValueProvider(ControllerContext ctlContext)12         {13             //if (!controllerContext.HttpContext.Request.ContentType.14             //    StartsWith("application/json", StringComparison.OrdinalIgnoreCase))15             //{16             //    return null;17             //}18 19             var reader = new StreamReader(ctlContext.HttpContext.Request.InputStream);20             reader.BaseStream.Position = 0;21             var json = reader.ReadToEnd();22             if (string.IsNullOrEmpty(json))23                 return null;24 25             var jtoken = json.StartsWith("[") 26                 ? JArray.Parse(json) as JContainer27                 : JObject.Parse(json) as JContainer;28             return new JsonNetValueProvider(jtoken);29         }30     }31 32     public class JsonNetValueProvider : IValueProvider33     {34         private JContainer _jValue;35 36         public JsonNetValueProvider(JContainer jval)37         {38             _jValue = jval;39         }40 41         public bool ContainsPrefix(string prefix)42         {43             return true;44         }45 46         public ValueProviderResult GetValue(string key)47         {48             var jtoken = _jValue.SelectToken(key);49             if (jtoken == null)50             {51                 jtoken = _jValue;52             }53             return new JsonNetValueProviderResult(jtoken, key, null);54         }55     }56 57     public class JsonNetValueProviderResult : ValueProviderResult58     {59         private JToken _jtoken;60         public JsonNetValueProviderResult(JToken valueRaw, string key, CultureInfo info)61         {62             _jtoken = valueRaw;63         }64         public override object ConvertTo(Type type, CultureInfo culture)65         {66             return _jtoken?.ToObject(type);67         }68     }69 70     public class JsonNetModelBinder : DefaultModelBinder71     {72         public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)73         {74             var provider = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);75             return provider.ConvertTo(bindingContext.ModelType);76         }77     }78 }

2、然後再Application_Start或者Router初始化時調用下面代碼：

            //重設Json序列化方式，改用JSON.Net            ValueProviderFactories.Factories.Remove(ValueProviderFactories.Factories.                OfType<JsonValueProviderFactory>().FirstOrDefault());            ValueProviderFactories.Factories.Add(new JsonNetValueProviderFactory());            //重設系統的Binder，使Dictionary可以正常json            ModelBinders.Binders.DefaultBinder = new JsonNetModelBinder();

原理基本上就是替換系統內建的ValueProviderFactory和DefaultModelBinder，然後改用自己的類來調用JSON.Net實現。

3、序列化的過程比較簡單，建立一個JsonNetResult類，然後mvc方法返回這個類型就可以了。

 public class JsonNetResult : JsonResult    {        public JsonSerializerSettings Settings { get; private set; }        public override void ExecuteResult(ControllerContext context)        {            //if (context == null)            //    throw new ArgumentNullException("context");            //if (this.JsonRequestBehavior == JsonRequestBehavior.DenyGet && string.Equals(context.HttpContext.Request.HttpMethod, "GET", StringComparison.OrdinalIgnoreCase))            //    throw new InvalidOperationException("JSON GET is not allowed");            HttpResponseBase response = context.HttpContext.Response;            response.ContentType = string.IsNullOrEmpty(this.ContentType) ? "application/json" : this.ContentType;            if (this.ContentEncoding != null)                response.ContentEncoding = this.ContentEncoding;            if (this.Data == null)                return;            var scriptSerializer = JsonSerializer.Create(this.Settings);            using (var sw = new StringWriter())            {                scriptSerializer.Serialize(sw, this.Data);                response.Write(sw.ToString());            }        }    }

 

使用JSON.Net（Newtonsoft.Json）作為ASP.Net MVC的json序列化和還原序列化工具