Singleton 泛型实例

抽象单类模式

public abstract class Singleton<T>  where T : new()
{
        private static T instance;
        private static readonly object loca = new object();

        public static T Instance
        {
            get
            {
                if (instance == null)
                {
                    lock (loca)
                    {
                        if (instance == null)
                        {
                            instance = new T();
                        }
                    }
                }

                return instance;
            }
        }
}