在.NET使用JSON作为数据交换格式

来源:岁月联盟 编辑:exp 时间:2012-03-27

我们知道在.NET中我们有多种对象序列化的方式,如XML方式序列化、Binary序列化,其中XML序列化是一种比较通用的在各语言之间传递数据的方式。除了这两种序列化方式之外,在.NET中还可以使用JSON序列化。
JSON(JavaScript Object Notation)是一种轻量级轻量级的数据交换格式,并且它独立于编程语言,与XML序列化相比,JSON序列化后产生的数据一般要比XML序列化后数据体积小,所以在Facebook等知名网站中都采用了JSON作为数据交换方式。在.NET中有三种常用的JSON序列化的类,分别是System.Web.Script.Serialization.JavaScriptSerializer类、System.Runtime.Serialization.Json.DataContractJsonSerializer类和Newtonsoft.Json.JsonConvert类。
为了便于下面的演示,下面提供一个类的代码:
[DataContract] 
public class User 

    /// <summary> 
    /// 编号 
    /// </summary> 
    [DataMember] 
    public int UserId { get; set; } 
    /// <summary> 
    /// 用户名 
    /// </summary> 
    [DataMember] 
    public string UserName { get; set; } 
    /// <summary> 
    /// 创建时间 
    /// </summary> 
    [DataMember] 
    [JsonConverter(typeof(IsoDateTimeConverter))] 
    public DateTime CreateDate { get; set; } 
    /// <summary> 
    /// 生日 
    /// </summary> 
    [DataMember] 
    [JsonConverter(typeof(JavaScriptDateTimeConverter))] 
    public DateTime Birthday { get; set; } 
    /// <summary> 
    /// 相关URL 
    /// </summary> 
    [DataMember] 
    public List<string> Urls { get; set; } 
    /// <summary> 
    /// 薪水 
    /// </summary> 
    //[ScriptIgnore]//使用JavaScriptSerializer序列化时不序列化此字段 
    //[IgnoreDataMember]//使用DataContractJsonSerializer序列化时不序列化此字段 
    //[JsonIgnore]//使用JsonConvert序列化时不序列化此字段 
    public int Salary { get; set; } 
    /// <summary> 
    /// 权利级别 
    /// </summary> 
    [DataMember] 
    public Priority Priority { get; set; } 
 
    public User() 
    { 
        Urls = new List<string>(); 
    } 

/// <summary> 
/// 权利级别 
/// </summary> 
public enum Priority:byte 

    Lowest=0x1, 
    BelowNormal=0x2, 
    Normal=0x4, 
    AboveNormal=0x8, 
    Highest=0x16 

使用System.Web.Script.Serialization.JavaScriptSerializer类
System.Web.Script.Serialization.JavaScriptSerializer类是.NET类库中自带的一种JSON序列化实现,在.NET Framework3.5及以后版本中可以使用这个类,这个类位于System.Web.Extensions.dll中,使用这个类是必须添加对这个dll的引用。
下面的代码是使用JavaScriptSerializer进行序列化和反序列化的例子:
public static void JavaScriptSerializerDemo() 

    User user = new User { UserId = 1, UserName = "李刚", CreateDate = DateTime.Now.AddYears(-30),Birthday=DateTime.Now.AddYears(-50), Priority = Priority.Highest, Salary = 500000 }; 
    //JavaScriptSerializer类在System.Web.Extensions.dll中,注意添加这个引用 
    JavaScriptSerializer serializer = new JavaScriptSerializer(); 
    //JSON序列化 
    string result=serializer.Serialize(user); 
    Console.WriteLine("使用JavaScriptSerializer序列化后的结果:{0},长度:{1}", result, result.Length); 
    //JSON反序列化 
    user = serializer.Deserialize<User>(result); 
    Console.WriteLine("使用JavaScriptSerializer反序列化后的结果:UserId:{0},UserName:{1},CreateDate:{2},Priority:{3}", user.UserId, user.UserName, user.CreateDate, user.Priority); 
 

说明:如果不想序列化某个字段,可以在字段前面加[JsonIgnore]标记。

使用System.Runtime.Serialization.Json.DataContractJsonSerializer类
System.Runtime.Serialization.Json.DataContractJsonSerializer类位于System.ServiceModel.Web.dll中,使用这个类时除了需要添加对System.ServiceModel.Web.dll的引用之外,还需要添加System.Runtime.Serialization.dll的引用,注意这个类也是在.NET Framework3.5及以后版本中可以使用。
下面是使用DataContractJsonSerializer类的例子:
public static void DataContractJsonSerializerDemo() 

    User user = new User { UserId = 1, UserName = "李刚", CreateDate = DateTime.Now.AddYears(-30), Birthday = DateTime.Now.AddYears(-50), Priority = Priority.AboveNormal, Salary = 50000 }; 
    string result = string.Empty; 
    //DataContractJsonSerializer类在System.ServiceModel.Web.dll中,注意添加这个引用 
    DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(User)); 
     
    using (MemoryStream stream = new MemoryStream()) 
    { 
        //JSON序列化 
        serializer.WriteObject(stream, user); 
        result = Encoding.UTF8.GetString(stream.ToArray()); 
        Console.WriteLine("使用DataContractJsonSerializer序列化后的结果:{0},长度:{1}", result, result.Length); 
    } 
 
    //JSON反序列化 
    byte[] buffer = Encoding.UTF8.GetBytes(result); 
    using (MemoryStream stream = new MemoryStream(buffer)) 
    { 
        user = serializer.ReadObject(stream) as User; 
        Console.WriteLine("使用DataContractJsonSerializer反序列化后的结果:UserId:{0},UserName:{1},CreateDate:{2},Priority:{3}", user.UserId, user.UserName, user.CreateDate, user.Priority); 
    } 

注意:要使用DataContractJsonSerializer类进行序列化和反序列化,必须给类加上[DataContract]属性,对要序列化的字段加上[DataMember]属性,如果不想序列化某个字段或者属性,可以加上[IgnoreDataMember]属性。

使用Newtonsoft.Json.JsonConvert类
Newtonsoft.Json.JsonConvert类是非微软提供的一个JSON序列化和反序列的开源免费的类库(下载网址是:http://www.codeplex.com/json/),它提供了更灵活的序列化和反序列化控制,并且如果你的开发环境使用的是.NET Framework3.5及以后版本的话,你就可以使用Linq to JSON,这样一来面对一大段的数据不必一一解析,你可以使用Linq to JSON解析出你关心的那部分即可,非常方便。
下面是使用Newtonsoft.Json.JsonConvert类的例子:
public static void JsonConvertDemo() 

    User user = new User { UserId = 1, UserName = "李刚", CreateDate = DateTime.Now.AddYears(-30), Birthday = DateTime.Now.AddYears(-50), Priority = Priority.BelowNormal, Salary = 5000 }; 
    //JsonConvert类在Newtonsoft.Json.Net35.dll中,注意到http://www.codeplex.com/json/下载这个dll并添加这个引用 
    //JSON序列化 
    string result = JsonConvert.SerializeObject(user); 
    Console.WriteLine("使用JsonConvert序列化后的结果:{0},长度:{1}", result, result.Length); 
    //JSON反序列化 
    user = JsonConvert.DeserializeObject<User>(result); 
    Console.WriteLine("使用JsonConvert反序列化后的结果:UserId:{0},UserName:{1},CreateDate:{2},Priority:{3}", user.UserId, user.UserName, user.CreateDate, user.Priority); 

 
public static void JsonConvertLinqDemo() 

    User user = new User { UserId = 1, UserName = "周公", CreateDate = DateTime.Now.AddYears(-8), Birthday = DateTime.Now.AddYears(-32), Priority = Priority.Lowest, Salary = 500, Urls = new List<string> { "http://zhoufoxcn.blog.51cto.com", "http://blog.csdn.net/zhoufoxcn" } }; 
    //JsonConvert类在Newtonsoft.Json.Net35.dll中,注意到http://www.codeplex.com/json/下载这个dll并添加这个引用 
    //JSON序列化 
    string result = JsonConvert.SerializeObject(user); 
    Console.WriteLine("使用JsonConvert序列化后的结果:{0},长度:{1}", result, result.Length); 
    //使用Linq to JSON 
    JObject jobject = JObject.Parse(result); 
    JToken token = jobject["Urls"]; 
    List<string> urlList = new List<string>(); 
    foreach (JToken t in token) 
    { 
        urlList.Add(t.ToString()); 
    } 
    Console.Write("使用Linq to JSON反序列化后的结果:["); 
    for (int i = 0; i < urlList.Count - 1;i++ ) 
    { 
        Console.Write(urlList[i] + ","); 
    } 
    Console.WriteLine(urlList[urlList.Count - 1] + "]"); 

注意:如果有不需要序列化的字段,可以给该字段添加[JsonIgnore]标记。在Newtonsoft这个类库中对于日期的序列化有多种方式,可以类的DataTime成员添加上对应的标记,这样在进行序列化和反序列化时就会按照指定的方式进行,在本例中User类的CreateDate属性添加的属性是[JsonConverter(typeof(IsoDateTimeConverter))],而Birthday属性添加的属性是[JsonConverter(typeof(JavaScriptDateTimeConverter))],从序列化的结果可以看出来它们最终的表现形式并不一样。
本文中所有的示例代码如下:
using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Web.Script.Serialization; 
using System.Runtime.Serialization.Json; 
using System.IO; 
using System.Runtime.Serialization; 
using Newtonsoft.Json; 
using Newtonsoft.Json.Linq; 
using Newtonsoft.Json.Converters; 
 
namespace JSONDemo 

class Program 

    static void Main(string[] args) 
    { 
        JavaScriptSerializerDemo(); 
        DataContractJsonSerializerDemo(); 
        JsonConvertDemo(); 
        JsonConvertLinqDemo(); 
        Console.ReadLine(); 
    } 
 
    public static void JavaScriptSerializerDemo() 
    { 
        User user = new User { UserId = 1, UserName = "李刚", CreateDate = DateTime.Now.AddYears(-30),Birthday=DateTime.Now.AddYears(-50), Priority = Priority.Highest, Salary = 500000 }; 
        //JavaScriptSerializer类在System.Web.Extensions.dll中,注意添加这个引用 
        JavaScriptSerializer serializer = new JavaScriptSerializer(); 
        //JSON序列化 
        string result=serializer.Serialize(user); 
        Console.WriteLine("使用JavaScriptSerializer序列化后的结果:{0},长度:{1}", result, result.Length); 
        //JSON反序列化 
        user = serializer.Deserialize<User>(result); 
        Console.WriteLine("使用JavaScriptSerializer反序列化后的结果:UserId:{0},UserName:{1},CreateDate:{2},Priority:{3}", user.UserId, user.UserName, user.CreateDate, user.Priority); 
 
    } 
 
    public static void DataContractJsonSerializerDemo() 
    { 
        User user = new User { UserId = 1, UserName = "李刚", CreateDate = DateTime.Now.AddYears(-30), Birthday = DateTime.Now.AddYears(-50), Priority = Priority.AboveNormal, Salary = 50000 }; 
        string result = string.Empty; 
        //DataContractJsonSerializer类在System.ServiceModel.Web.dll中,注意添加这个引用 
        DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(User)); 
         
        using (MemoryStream stream = new MemoryStream()) 
        { 
            //JSON序列化 
            serializer.WriteObject(stream, user); 
            result = Encoding.UTF8.GetString(stream.ToArray()); 
            Console.WriteLine("使用DataContractJsonSerializer序列化后的结果:{0},长度:{1}", result, result.Length); 
        } 
 
        //JSON反序列化 
        byte[] buffer = Encoding.UTF8.GetBytes(result); 
        using (MemoryStream stream = new MemoryStream(buffer)) 
        { 
            user = serializer.ReadObject(stream) as User; 
            Console.WriteLine("使用DataContractJsonSerializer反序列化后的结果:UserId:{0},UserName:{1},CreateDate:{2},Priority:{3}", user.UserId, user.UserName, user.CreateDate, user.Priority); 
        } 
    } 
 
    public static void JsonConvertDemo() 
    { 
        User user = new User { UserId = 1, UserName = "李刚", CreateDate = DateTime.Now.AddYears(-30), Birthday = DateTime.Now.AddYears(-50), Priority = Priority.BelowNormal, Salary = 5000 }; 
        //JsonConvert类在Newtonsoft.Json.Net35.dll中,注意到http://www.codeplex.com/json/下载这个dll并添加这个引用 
        //JSON序列化 
        string result = JsonConvert.SerializeObject(user); 
        Console.WriteLine("使用JsonConvert序列化后的结果:{0},长度:{1}", result, result.Length); 
        //JSON反序列化 
        user = JsonConvert.DeserializeObject<User>(result); 
        Console.WriteLine("使用JsonConvert反序列化后的结果:UserId:{0},UserName:{1},CreateDate:{2},Priority:{3}", user.UserId, user.UserName, user.CreateDate, user.Priority); 
    } 
 
    public static void JsonConvertLinqDemo() 
    { 
        User user = new User { UserId = 1, UserName = "周公", CreateDate = DateTime.Now.AddYears(-8), Birthday = DateTime.Now.AddYears(-32), Priority = Priority.Lowest, Salary = 500, Urls = new List<string> { "http://zhoufoxcn.blog.51cto.com", "http://blog.csdn.net/zhoufoxcn" } }; 
        //JsonConvert类在Newtonsoft.Json.Net35.dll中,注意到http://www.codeplex.com/json/下载这个dll并添加这个引用 
        //JSON序列化 
        string result = JsonConvert.SerializeObject(user); 
        Console.WriteLine("使用JsonConvert序列化后的结果:{0},长度:{1}", result, result.Length); 
        //使用Linq to JSON 
        JObject jobject = JObject.Parse(result); 
        JToken token = jobject["Urls"]; 
        List<string> urlList = new List<string>(); 
        foreach (JToken t in token) 
        { 
            urlList.Add(t.ToString()); 
        } 
        Console.Write("使用Linq to JSON反序列化后的结果:["); 
        for (int i = 0; i < urlList.Count - 1;i++ ) 
        { 
            Console.Write(urlList[i] + ","); 
        } 
        Console.WriteLine(urlList[urlList.Count - 1] + "]"); 
    } 

 
[DataContract] 
public class User 

    /// <summary> 
    /// 编号 
    /// </summary> 
    [DataMember] 
    public int UserId { get; set; } 
    /// <summary> 
    /// 用户名 
    /// </summary> 
    [DataMember] 
    public string UserName { get; set; } 
    /// <summary> 
    /// 创建时间 
    /// </summary> 
    [DataMember] 
    [JsonConverter(typeof(IsoDateTimeConverter))] 
    public DateTime CreateDate { get; set; } 
    /// <summary> 
    /// 生日 
    /// </summary> 
    [DataMember] 
    [JsonConverter(typeof(JavaScriptDateTimeConverter))] 
    public DateTime Birthday { get; set; } 
    /// <summary> 
    /// 相关URL 
    /// </summary> 
    [DataMember] 
    public List<string> Urls { get; set; } 
    /// <summary> 
    /// 薪水 
    /// </summary> 
    [ScriptIgnore]//使用JavaScriptSerializer序列化时不序列化此字段 
    [IgnoreDataMember]//使用DataContractJsonSerializer序列化时不序列化此字段 
    [JsonIgnore]//使用JsonConvert序列化时不序列化此字段 
    public int Salary { get; set; } 
    /// <summary> 
    /// 权利级别 
    /// </summary> 
    [DataMember] 
    public Priority Priority { get; set; } 
 
    public User() 
    { 
        Urls = new List<string>(); 
    } 

/// <summary> 
/// 权利级别 
/// </summary> 
public enum Priority:byte 

    Lowest=0x1, 
    BelowNormal=0x2, 
    Normal=0x4, 
    AboveNormal=0x8, 
    Highest=0x16 

程序的运行结果如下:
[xhtml]
使用JavaScriptSerializer序列化后的结果:{"UserId":1,"UserName":"李刚","CreateDate":"//Date(353521211984)//","Birthday":"//Date(-277630788015)//","Urls":[],"Priority":22},长度:127 
使用JavaScriptSerializer反序列化后的结果:UserId:1,UserName:李刚,CreateDate:1981-3-15 16:20:11,Priority:Highest 
使用DataContractJsonSerializer序列化后的结果:{"Birthday":"//Date(-277630787953+0800)//","CreateDate":"//Date(353521212046+0800)//","Priority":8,"Urls":[],"UserId":1,"UserName":"李刚"},长度:136 
使用DataContractJsonSerializer反序列化后的结果:UserId:1,UserName:李刚,CreateDate:1981-3-16 0:20:12,Priority:AboveNormal 
使用JsonConvert序列化后的结果:{"UserId":1,"UserName":"李刚","CreateDate":"1981-03-16T00:20:12.1875+08:00","Birthday":new Date(-277630787812),"Urls":[],"Priority":2},长度:132 
使用JsonConvert反序列化后的结果:UserId:1,UserName:李刚,CreateDate:1981-3-16 0:20:12,Priority:BelowNormal 
使用JsonConvert序列化后的结果:{"UserId":1,"UserName":"周公","CreateDate":"2003-03-16T00:20:12.40625+08:00","Birthday":new Date(290362812406),"Urls":["http://zhoufoxcn.blog.51cto.com","http://blog.csdn.net/zhoufoxcn"],"Priority":1},长度:198 
使用Linq to JSON反序列化后的结果:["http://zhoufoxcn.blog.51cto.com","http://blog.csdn.net/zhoufoxcn"] 

总结:通过上面的例子大家可以看出Newtonsoft类库提供的JSON序列化和反序列的方式更加灵活,在实际开发中周公也一直使用Newtonsoft作为JSON序列化和反序列化的不二选择。 


摘自  SYZ_YUMEIZHOU_YY