using System;using System.Linq;using System.Reflection;namespace DotnetSpider.Core.Infrastructure{    /// 
    /// 单独的泛型实型    /// 
    /// 
        public abstract class Singleton
    
         {        private static readonly Lazy
     
       MyInstance = new Lazy
      
       (() =>        {            var ctors = typeof(T).GetConstructors(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);            if (ctors.Length != 1)            {                throw new InvalidOperationException($"Type {typeof(T)} must have exactly one constructor.");            }            var ctor = ctors.SingleOrDefault(c => !c.GetParameters().Any() && c.IsPrivate);            if (ctor == null)            {                throw new InvalidOperationException($"The constructor for {typeof(T)} must be private and take no parameters.");            }            return (T)ctor.Invoke(null);        });        /// 
       
        /// 单例对象        /// 
        public static T Instance => MyInstance.Value;    }}