C#操作JSON_.NET_编程开发_程序员俱乐部

class="MsoNormal" style="text-align: center;" align="center">C#操作JSON

1. .NET对JSON的支持介绍....................................................... 1

(1) 操作Json的DLL介绍..................................................... 1

(2) 使用System.Web.Extensions.dll的限制............... 1

2. JSON序列化和反序列化.......................................................... 1

(1) 使用Newtonsoft.Json.dll实现................................. 1

(2) 使用System.Web.Extensions.dll实现.................... 2

(3) 使用System.Runtime.Serialization.dll实现.... 3

(4) 小结..................................................................................... 5

3. 解析JSON字符串(使用Newtonsoft.Json.dll).............. 5

(1) 使用JsonTextReader类进行只进读取(不常用)...... 5

(2) 使用JArray、JObject、JToken进行读取(常用)... 5

(3) Json时间字符串的处理.................................................. 6

4. 读取Json字符串的技巧......................................................... 6

(1) 使用匿名类........................................................................ 6

(2) 使用索引器........................................................................ 6

 

1..NET对JSON的支持介绍

(1)操作Json的DLL介绍

.NET自身有System.Runtime.Serialization.dll与System.Web.Extensions.dll，使用这两个DLL可以把对象序列化和反序列化成Json数据。

也可以使用第三方的Newtonsoft.Json.dll来操作Json数据，使用它会更方便的操作Json数据，其功能也跟强一些。下载地址：http://json.codeplex.com/

(2)使用System.Web.Extensions.dll的限制

要使用System.Web.Extensions.dll必须是在Web项目中，只有在Web项目中才能引用此DLL。

2.JSON序列化和反序列化

(1)使用Newtonsoft.Json.dll实现

代码示例：

    public class Person

    {

        public string Name;//姓名

        public bool Sex;//性别，是否是男

        public Person(string name, bool sex)

        {

            this.Name = name;

            this.Sex = sex;

        }

        public override string ToString()

        {

            return "姓名：" + this.Name + "\t性别：" + (this.Sex ? "男" : "女");

        }

    }

    public class Programmer : Person

    {

        public List<string> Languages;//编程语言

        public Programmer(string name, bool sex, List<string> languages) : base(name, sex)

        {

            this.Languages = languages;

        }

        public override string ToString()

        {

            StringBuilder str = new StringBuilder();

            str.Append(base.ToString() + "\t编程语言：");

            foreach (string l in this.Languages)

            {

                str.Append(l + " ");

            }

            return str.ToString();

        }

    }

    class Program

    {

        static void Main(string[] args)

        {

            string filePath = @"D:\users\lizw\桌面\ObjectJson.txt";

            List<string> languages = null;

            List<Programmer> list = new List<Programmer>();

            languages = new List<string>(new string[] { "C#", "Java" });

            list.Add(new Programmer("李志伟", true, languages));

            languages = new List<string>(new string[] { "C#", "C++" });

            list.Add(new Programmer("Coder2", false, languages));

            languages = new List<string>(new string[] { "C#", "C++", "C", "Java" });

            list.Add(new Programmer("Coder3", true, languages));

            //序列化对象

            string jsonStr = JsonConvert.SerializeObject(list);//将对象转换成json存储

            File.WriteAllText(filePath, jsonStr);

            list.Clear();

            //反序列化对象

            list = JsonConvert.DeserializeObject<List<Programmer>>(jsonStr);

            foreach (Programmer p in list)

            {

                Console.WriteLine(p);

            }

            Console.WriteLine("OK!");

            Console.Read();

        }

    }

得到的Json文本：

[{"Languages":["C#","Java"],"Name":"李志伟","Sex":true},

{"Languages":["C#","C++"],"Name":"Coder2","Sex":false},

{"Languages":["C#","C++","C","Java"],"Name":"Coder3","Sex":true}]

注意：此种方式Json序列化对象时，只能序列化对象的公有成员。

(2)使用System.Web.Extensions.dll实现

代码示例：

    public class Person

    {

        public string Name;//姓名

        public bool Sex;//性别，是否是男

        public Person() { }//必须有此构造方法，否者无法反序列化

        public Person(string name, bool sex)

        {

            this.Name = name;

            this.Sex = sex;

        }

        public override string ToString()

        {

            return "姓名：" + this.Name + "\t性别：" + (this.Sex ? "男" : "女");

        }

    }

    public class Programmer : Person

    {

        public List<string> Languages;//编程语言

        public Programmer() { }//必须有此构造方法，否者无法反序列化

        public Programmer(string name, bool sex, List<string> languages)

            : base(name, sex)

        {

            this.Languages = languages;

        }

        public override string ToString()

        {

            StringBuilder str = new StringBuilder();

            str.Append(base.ToString() + "\t编程语言：");

            foreach (string l in this.Languages)

            {

                str.Append(l + " ");

            }

            return str.ToString();

        }

    }

    public partial class WebForm1 : System.Web.UI.Page

    {

        protected void Page_Load(object sender, EventArgs e)//Web页面的加载事件

        {

            List<string> languages = null;

            List<Programmer> list = new List<Programmer>();

            languages = new List<string>(new string[] { "C#", "Java" });

            list.Add(new Programmer("李志伟", true, languages));

            languages = new List<string>(new string[] { "C#", "C++" });

            list.Add(new Programmer("Coder2", false, languages));

            languages = new List<string>(new string[] { "C#", "C++", "C", "Java" });

            list.Add(new Programmer("Coder3", true, languages));

            //序列化对象

            JavaScriptSerializer jsonSerialize = new JavaScriptSerializer();

            string jsonStr = jsonSerialize.Serialize(list);//将对象转换成json存储

            Response.Write(jsonStr + "<br>");//前台输出

            //反序列化对象

            list.Clear();

            list = jsonSerialize.Deserialize<List<Programmer>>(jsonStr);

            foreach (Programmer p in list)

            {

                Response.Write(p + "<br>");//前台输出

            }

        }

    }

得到的Json文本：

[{"Languages":["C#","Java"],"Name":"李志伟","Sex":true},

{"Languages":["C#","C++"],"Name":"Coder2","Sex":false},

{"Languages":["C#","C++","C","Java"],"Name":"Coder3","Sex":true}]

注意：此种方式Json序列化对象时，除了只能序列化对象的公有成员外，被序列化的对象还必须有无参的构造方法才能被反序列化！System.Web.Extensions.dll只能在Web项目中引用，在控制台和WinFrom项目中无法引用！

(3)使用System.Runtime.Serialization.dll实现

代码示例：

    [DataContract]//必须申明，否则无法序列化

    public class Person

    {

        [DataMember(Name = "姓名")]//必须申明，否则无法序列化

        private string Name;

        [DataMember(Name = "性别")]//必须申明，否则无法序列化

        private bool Sex;

        public Person(string name, bool sex)

        {

            this.Name = name;

            this.Sex = sex;

        }

        public override string ToString()

        {

            return "姓名：" + this.Name + "\t性别：" + (this.Sex ? "男" : "女");

        }

    }

    [DataContract]

    public class Programmer : Person

    {

        [DataMember(Name = "编程语言")]

        private List<string> Languages;

        public Programmer(string name, bool sex, List<string> languages)

            : base(name, sex)

        {

            this.Languages = languages;

        }

        public override string ToString()

        {

            StringBuilder str = new StringBuilder();

            str.Append(base.ToString() + "\t编程语言：");

            foreach (string l in this.Languages)

            {

                str.Append(l + " ");

            }

            return str.ToString();

        }

    }

    class Program

    {

        static void Main(string[] args)

        {

            string filePath = @"D:\users\lizw\桌面\ObjectJson.txt";

            List<string> languages = null;

            List<Programmer> list = new List<Programmer>();

            languages = new List<string>(new string[] { "C#", "Java" });

            list.Add(new Programmer("李志伟", true, languages));

            languages = new List<string>(new string[] { "C#", "C++" });

            list.Add(new Programmer("Coder2", false, languages));

            languages = new List<string>(new string[] { "C#", "C++", "C", "Java" });

            list.Add(new Programmer("Coder3", true, languages));

            //序列化对象

            DataContractJsonSerializer ser =

new DataContractJsonSerializer(typeof(List<Programmer>));

            MemoryStream ms = new MemoryStream();

            ser.WriteObject(ms, list);//将对象转换成json存储

            string jsonStr = Encoding.UTF8.GetString(ms.ToArray());

            File.WriteAllText(filePath, jsonStr);

            //反序列化对象

            list.Clear();

            ms.Position = 0;

            list = (List<Programmer>)ser.ReadObject(ms);

            foreach (Programmer p in list)

            {

                Console.WriteLine(p);

            }

            ms.Dispose();//关闭内存流

            Console.WriteLine("OK!");

            Console.Read();

        }

    }

得到的Json文本：

[{"姓名":"李志伟","性别":true,"编程语言":["C#","Java"]},

{"姓名":"Coder2","性别":false,"编程语言":["C#","C++"]},

{"姓名":"Coder3","性别":true,"编程语言":["C#","C++","C","Java"]}]

注意：此种方式Json序列化对象时，可以序列化对象的任意成员(包括私有成员)，但是使用此方式必须要在类和成员的定义处加上相应的特性(具体请参考代码)。

(4)小结

使用的DLL

序列化范围

项目范围

依赖构造器

依赖特性

Newtonsoft.Json.dll

公有成员

任意项目

否

否

System.Web.Extensions.dll

公有成员

Web项目

无参构造器

否

System.Runtime.Serialization.dll

所有成员

任意项目

否

是

3.解析JSON字符串(使用Newtonsoft.Json.dll)

(1)使用JsonTextReader类进行只进读取(不常用)

    class Program

    {

        static void Main(string[] args)

        {

            //Json字符串

            string jsonStr = @"

                [{'Languages':['C#','Java'],'Name':'李志伟','Sex':true},

                {'Languages':['C#','C++'],'Name':'Coder2','Sex':false},

                {'Languages':['C#','C++','C','Java'],'Name':'Coder3','Sex':true}]";

            JsonTextReader json = new JsonTextReader(new StringReader(jsonStr));

            while (json.Read())

            {

                Console.WriteLine(json.Value + "--" + json.TokenType + "--" + json.ValueType);

            }

            Console.WriteLine("OK!");

            Console.Read();

        }

    }

(2)使用JArray、JObject、JToken进行读取(常用)

    class Program

    {

        static void Main(string[] args)

        {

            //Json字符串

            string jsonStr = @"

                [{'Languages':['C#','Java'],'Name':'李志伟','Sex':true},

                {'Languages':['C#','C++'],'Name':'Coder2','Sex':false},

                {'Languages':['C#','C++','C','Java'],'Name':'Coder3','Sex':true}]";

            JArray ja = (JArray)JsonConvert.DeserializeObject(jsonStr);

            foreach (JToken jt in ja)

            {

                JObject jo = (JObject)jt;

                JArray temp = (JArray)jo["Languages"];

                foreach (JToken token in temp)

                {

                    Console.Write(token+" ");

                }

                Console.WriteLine("\t" + jo["Name"] + "\t" + jo["Sex"]);

            }

            Console.WriteLine("OK!");

            Console.Read();

        }

    }

(3)Json时间字符串的处理

    class Program

    {

        static void Main(string[] args)

        {

            DateTime time = DateTime.Now;

            //这里使用自定义日期格式

            IsoDateTimeConverter timeConverter = new IsoDateTimeConverter();

            timeConverter.DateTimeFormat = "北京时间：yyyy-MM-dd HH:mm:ss";

            //序列化时间

            string JsonStr = JsonConvert.SerializeObject(time, timeConverter);

            Console.WriteLine(JsonStr);

            //反序列化时间

            DateTime time2 = JsonConvert.DeserializeObject<DateTime>(JsonStr, timeConverter);

            Console.WriteLine(time2);

            Console.WriteLine("OK!");

            Console.Read();

        }

    }

4.读取Json字符串的技巧

(1)使用匿名类

    class Program

    {

        static void Main(string[] args)

        {

            //Json字符串

            string jsonStr = @"{'Languages':['C#','Java'],'Name':'李志伟','Sex':true}";

            //创建匿名类

            var TempClass = new { Languages = new string[0], Name = string.Empty, Sex = false };

            //反序列化

            var O = JsonConvert.DeserializeAnonymousType(jsonStr, TempClass);

            Console.WriteLine(O.Name+"\t"+O.Sex+"\t"+O.Languages[1]);

            Console.Read();

        }

    }

(2)使用索引器

    class Program

    {

        static void Main(string[] args)

        {

            //Json字符串

            string jsonStr = @"{'Languages':['C#','Java'],'Name':'李志伟','Sex':true}";

            //反序列化

            JObject O = JsonConvert.DeserializeObject(jsonStr) as JObject;

            //使用索引器访问

            Console.WriteLine(O["Name"] + "\t" + O["Sex"] + "\t" + O["Languages"][1]);

            Console.Read();

        }

    }