Json .net的用法

下面通过一个实例来展示它在项目的应用.下面的例子是通过Ajax和Json显示所有用户的列表信息.
准备: 创建一个Web项目,本应用程序是通过VS2010创建的.并添加引用Newtonsoft.Json.dll

1.首先创建一个Person对象

    /// <summary>    /// 包含用户的基本信息    /// </summary>    public class Person    {        /// <summary>        /// 获取或设置用户名        /// </summary>        public string Name { get; set; }        /// <summary>        /// 获取或设置用户年龄        /// </summary>        public int Age { get; set; }        /// <summary>        /// 获取或设置用户性别        /// </summary>        public string Gender { get; set; }        /// <summary>        /// 获取或设置用户国籍        /// </summary>        public string Country { get; set; }        /// <summary>        /// 获取或设置用户电子邮箱        /// </summary>        public string Email { get; set; }    }

2.创建用户操作类PersonRepository,用来对Person的操作,本例中仅仅用来获取Person对象列表

    /// <summary>    /// 用户操作类    /// </summary>    public class PersonRepository    {        /// <summary>        /// 获取用户列表        /// </summary>        /// <returns>所有用户信息</returns>        public static List<Person> GetPersons()        {            List<Person> ps = new List<Person>();            Person p1 = new Person { Name = "Tom", Age = 32, Country = "US", Gender = "Male", Email = "[e-mail]" };            Person p2 = new Person { Name = "Jack", Age = 23, Country = "UK", Gender = "Male", Email = "[e-mail]" };            Person p3 = new Person { Name = "Eden", Age = 25, Country = "Canada", Gender = "Female", Email = "[e-mail]" };            Person p4 = new Person { Name = "Li Hua", Age = 29, Country = "China", Gender = "Male", Email = "[e-mail]" };            Person p5 = new Person { Name = "Lvo", Age = 40, Country = "US", Gender = "Male", Email = "[e-mail]" };            ps.Add(p1);            ps.Add(p2);            ps.Add(p3);            ps.Add(p4);            ps.Add(p5);            return ps;        }    }

3.添加一个一般处理程序,我将其命名为PersonHandler.ashx,引入命名空间"using Newtonsoft.Json",修改ProcessRequest函数中的代码如下:

    /// <summary>    /// 处理用户类的请求    /// </summary>    public class PersonHandler : IHttpHandler    {        public void ProcessRequest(HttpContext context)        {            List<Person> persons = PersonRepository.GetPersons();            string json = JsonConvert.SerializeObject(persons);            context.Response.Write(json);        }        public bool IsReusable        {            get            {                return false;            }        }    }

通过Json.Net来序列化对象,可以通过

string json = JsonConvert.SerializeObject(Object obj);

 

还可以通过JsonSerializer来实现

              JsonSerializer serializer = new JsonSerializer();            StringBuilder sb = new StringBuilder();            StringWriter sw = new StringWriter(sb);            JsonWriter writer = new JsonTextWriter(sw);            serializer.Serialize(writer, persons);            string json = sb.ToString();

这两种方式有什么联系和区别呢?
实际上,JsonConvert.SerializerObject内部就是通过JsonSerializer来实现的.

public static string SerializeObject(object value, Formatting formatting, JsonSerializerSettings settings){    JsonSerializer jsonSerializer = JsonSerializer.Create(settings);    StringBuilder sb = new StringBuilder(0x100);    StringWriter sw = new StringWriter(sb, CultureInfo.InvariantCulture);    using (JsonTextWriter jsonWriter = new JsonTextWriter(sw))    {        jsonWriter.Formatting = formatting;        jsonSerializer.Serialize(jsonWriter, value);    }    return sw.ToString();} 

区别在于JsonSerializer序列化时,你可以选择用JsonWriter也可以选择TextWriter.而JsonConvert只是默认使用JsonTextWriter. 

4.添加一个Html网页,网页的内容仅仅用来显示用户的基本信息

    <div>        <table border="1">            <thead>                <tr>                 <td>                        用户名                    </td>                 <td>                        年龄                    </td>                 <td>                        性别                    </td>                 <td>                        国籍                    </td>                 <td>                        电子邮箱                    </td>                </tr>            </thead>            <tbody id="personBody">            </tbody>        </table>    </div>

5.添加javascript代码,实现Ajax请求.首先要在头文件中引入JQuery

    <script src="Scripts/jquery-1.4.1.min.js" type="text/javascript"></script>    <script type="text/javascript">        $(function () {            $.getJSON("PersonHandler.ashx", function (data, status) {                if (status == "success") {                    $.each(data, function (index, item) {                        var beginTag = "<tr><td>";                        var endTag = "</td></tr>";                        var tag = "</td><td>";                        $("#personBody").append($(beginTag + item.Name + tag + item.Age + tag + item.Gender + tag                        + item.Country + tag + item.Email + endTag));                    });                }            });        });    </script>

$.getJSON可以进行异步Ajax请求,并可以直接返回JSON对象

  jQuery.getJSON(url,data,success(data,status,xhr))   

 

参数说明

参数描述url必需。规定将请求发送的哪个 URL。data可选。规定连同请求发送到服务器的数据。success(data,status,xhr)

可选。规定当请求成功时运行的函数。

额外的参数：

• response - 包含来自请求的结果数据
• status - 包含请求的状态
• xhr - 包含 XMLHttpRequest 对象

 

 

 

 

 

 

 

 

 

 

运行效果: