C#实现简单的JSON序列化功能代码实例

 好久没有做web了，JSON目前比较流行，闲得没事，所以动手试试将对象序列化为JSON字符（尽管DotNet Framework已经有现成的库，也有比较好的第三方开源库）,而且只是实现了处理简单的类型,并且DateTime处理的也不专业，有兴趣的筒子可以扩展，代码比较简单，反序列化木有实现:( ，直接贴代码吧，都有注释了，所以废话不多说  :)

测试类/// <summary>
    /// Nested class of Person.
    /// </summary>
    public class House
    {
        public string Name
        {
            get;
            set;
        }
        public double Price
        {
            get;
            set;
        }
    }

    /// <summary>
    /// Person dummy class
    /// </summary>
    public class Person
    {
        public string Name
        {
            get;
            set;
        }
        public int Age
        {
            get;
            set;
        }
        public string Address
        {
            get;
            set;
        }
        private int h = 12;

        public bool IsMarried
        {
            get;
            set;
        }

        public string[] Names
        {
            get;
            set;
        }

        public int[] Ages
        {
            get;
            set;
        }
        public House MyHouse
        {
            get;
            set;
        }
        public DateTime BirthDay
        {
            get;
            set;
        }
        public List<string> Friends
        {
            get;
            set;
        }
        public List<int> LoveNumbers
        {
            get;
            set;
        }
    }

接口定义  /// <summary>
    /// IJsonSerializer interface.
    /// </summary>
    interface IJsonSerializer
    {
        /// <summary>
        /// Serialize object to json string.
        /// </summary>
        /// <typeparam name="T">The type to be serialized.</typeparam>
        /// <param name="obj">Instance of the type T.</param>
        /// <returns>json string.</returns>
        string Serialize(object obj);

        /// <summary>
        /// Deserialize json string to object.
        /// </summary>
        /// <typeparam name="T">The type to be deserialized.</typeparam>
        /// <param name="jsonString">json string.</param>
        /// <returns>instance of type T.</returns>
        T Deserialize<T>(string jsonString);
    }

接口实现，还有待完善..

/// <summary>
    /// Implement IJsonSerializer, but Deserialize had not been implemented.
    /// </summary>
    public class JsonSerializer : IJsonSerializer
    {
        /// <summary>
        /// Serialize object to json string.
        /// </summary>
        /// <typeparam name="T">The type to be serialized.</typeparam>
        /// <param name="obj">Instance of the type T.</param>
        /// <returns>json string.</returns>
        public string Serialize(object obj)
        {
            if (obj == null)
            {
                return "{}";
            }

            // Get the type of obj.
            Type t = obj.GetType();

            // Just deal with the public instance properties. others ignored.
            BindingFlags bf = BindingFlags.Instance | BindingFlags.Public;

            PropertyInfo[] pis = t.GetProperties(bf);

            StringBuilder json = new StringBuilder("{");

            if (pis != null && pis.Length > 0)
            {
                int i = 0;
                int lastIndex = pis.Length - 1;

                foreach (PropertyInfo p in pis)
                {
                    // Simple string
                    if (p.PropertyType.Equals(typeof(string)))
                    {
                        json.AppendFormat("\"{0}\":\"{1}\"", p.Name, p.GetValue(obj, null));
                    }
                    // Number,boolean.
                    else if (p.PropertyType.Equals(typeof(int)) ||
                        p.PropertyType.Equals(typeof(bool)) ||
                        p.PropertyType.Equals(typeof(double)) ||
                        p.PropertyType.Equals(typeof(decimal))
                        )
                    {
                        json.AppendFormat("\"{0}\":{1}", p.Name, p.GetValue(obj, null).ToString().ToLower());
                    }
                    // Array.
                    else if (isArrayType(p.PropertyType))
                    {
                        // Array case.
                        object o = p.GetValue(obj, null);

                        if (o == null)
                        {
                            json.AppendFormat("\"{0}\":{1}", p.Name, "null");
                        }
                        else
                        {
                            json.AppendFormat("\"{0}\":{1}", p.Name, getArrayValue((Array)p.GetValue(obj, null)));
                        }
                    }
                    // Class type. custom class, list collections and so forth.
                    else if (isCustomClassType(p.PropertyType))
                    {
                        object v = p.GetValue(obj, null);
                        if (v is IList)
                        {
                            IList il = v as IList;
                            string subJsString = getIListValue(il);

                            json.AppendFormat("\"{0}\":{1}", p.Name, subJsString);
                        }
                        else
                        {
                            // Normal class type.
                            string subJsString = Serialize(p.GetValue(obj, null));

                            json.AppendFormat("\"{0}\":{1}", p.Name, subJsString);
                        }
                    }
                    // Datetime
                    else if (p.PropertyType.Equals(typeof(DateTime)))
                    {
                        DateTime dt = (DateTime)p.GetValue(obj, null);

                        if (dt == default(DateTime))
                        {
                            json.AppendFormat("\"{0}\":\"\"", p.Name);
                        }
                        else
                        {
                            json.AppendFormat("\"{0}\":\"{1}\"", p.Name, ((DateTime)p.GetValue(obj, null)).ToString("yyyy-MM-dd HH:mm:ss"));
                        }
                    }
                    else
                    {
                        // TODO: extend.
                    }

                    if (i >= 0 && i != lastIndex)
                    {
                        json.Append(",");
                    }

                    ++i;
                }
            }

            json.Append("}");

            return json.ToString();
        }

        /// <summary>
        /// Deserialize json string to object.
        /// </summary>
        /// <typeparam name="T">The type to be deserialized.</typeparam>
        /// <param name="jsonString">json string.</param>
        /// <returns>instance of type T.</returns>
        public T Deserialize<T>(string jsonString)
        {
            throw new NotImplementedException("Not implemented :(");
        }

        /// <summary>
        /// Get array json format string value.
        /// </summary>
        /// <param name="obj">array object</param>
        /// <returns>js format array string.</returns>
        string getArrayValue(Array obj)
        {
            if (obj != null)
            {
                if (obj.Length == 0)
                {
                    return "[]";
                }

                object firstElement = obj.GetValue(0);
                Type et = firstElement.GetType();
                bool quotable = et == typeof(string);

                StringBuilder sb = new StringBuilder("[");
                int index = 0;
                int lastIndex = obj.Length - 1;

                if (quotable)
                {
                    foreach (var item in obj)
                    {
                        sb.AppendFormat("\"{0}\"", item.ToString());

                        if (index >= 0 && index != lastIndex)
                        {
                            sb.Append(",");
                        }

                        ++index;
                    }
                }
                else
                {
                    foreach (var item in obj)
                    {
                        sb.Append(item.ToString());

                        if (index >= 0 && index != lastIndex)
                        {
                            sb.Append(",");
                        }

                        ++index;
                    }
                }

                sb.Append("]");

                return sb.ToString();
            }

            return "null";
        }

        /// <summary>
        /// Get Ilist json format string value.
        /// </summary>
        /// <param name="obj">IList object</param>
        /// <returns>js format IList string.</returns>
        string getIListValue(IList obj)
        {
            if (obj != null)
            {
                if (obj.Count == 0)
                {
                    return "[]";
                }

                object firstElement = obj[0];
                Type et = firstElement.GetType();
                bool quotable = et == typeof(string);

                StringBuilder sb = new StringBuilder("[");
                int index = 0;
                int lastIndex = obj.Count - 1;

                if (quotable)
                {
                    foreach (var item in obj)
                    {
                        sb.AppendFormat("\"{0}\"", item.ToString());

                        if (index >= 0 && index != lastIndex)
                        {
                            sb.Append(",");
                        }

                        ++index;
                    }
                }
                else
                {
                    foreach (var item in obj)
                    {
                        sb.Append(item.ToString());

                        if (index >= 0 && index != lastIndex)
                        {
                            sb.Append(",");
                        }

                        ++index;
                    }
                }

                sb.Append("]");

                return sb.ToString();
            }

            return "null";
        }

        /// <summary>
        /// Check whether t is array type.
        /// </summary>
        /// <param name="t"></param>
        /// <returns></returns>
        bool isArrayType(Type t)
        {
            if (t != null)
            {
                return t.IsArray;
            }

            return false;
        }

        /// <summary>
        /// Check whether t is custom class type.
        /// </summary>
        /// <param name="t"></param>
        /// <returns></returns>
        bool isCustomClassType(Type t)
        {
            if (t != null)
            {
                return t.IsClass && t != typeof(string);
            }

            return false;
        }
    }

测试代码：

class Program
    {
        static void Main(string[] args)
        {
            Person ps = new Person()
            {
                Name = "Leon",
                Age = 25,
                Address = "China",
                IsMarried = false,
                Names = new string[] { "wgc", "leon", "giantfish" },
                Ages = new int[] { 1, 2, 3, 4 },
                MyHouse = new House()
                {
                    Name = "HouseName",
                    Price = 100.01,
                },
                BirthDay = new DateTime(1986, 12, 20, 12, 12, 10),
                Friends = new List<string>() { "friend1", "friend2" },
                LoveNumbers = new List<int>() { 1, 2, 3 }
            };

            IJsonSerializer js = new JsonSerializer();
            string s = js.Serialize(ps);
            Console.WriteLine(s);
            Console.ReadKey();
        }
    }

 生成的 JSON字符串 ： 

 {"Name":"Leon","Age":25,"Address":"China","IsMarried":false,"Names":["wgc","leon","giantfish"],"Ages":[1,2,3,4],"MyHouse":{"Name":"HouseName","Price":100.01},"BirthDay":"1986-12-20 12:12:10","Friends":["friend1","friend2"],"LoveNumbers":[1,2,3]}