原型模式之深浅复制

前言

    原型模式也写过一篇博客《原型模式》，但是深浅复制没有细讲，这一次学习原型时，深浅复制虽然思想清楚，但对应到代码时却糊涂了，经过与它人交流讨论与思考，已明白其原理。

浅复制

<span style="font-size:18px;">    class WordExperience:ICloneable
    {
       private string workDate;
       public string WorkDate
       {
          get { return workDate; }
          set { workDate = value; }
       }
       private string company;
       public string company
       {
          get { return company; }
          set { company= value; }
       }
       
    }
 
    //简历
    class Resume :ICloneable
    {
        private string name;
        private string sex;
        private string age;
        
        private WorkExperience work;
 
 
        public Resume(string name)
        {
            this.name = name;
            work = new WorkExperience();
        }
        public void SetPersonalInfo(string sex, string age)
        {
            this.sex = sex;
            this.age = age;
        }
        //工作经历
        public void SetWorkExperience(string workDate, string company)
        {
            this.WorkDate = workDate;
            this.company = company;
        }
       //显示
        public void Display()
        {
            Console.WriteLine("{0} {1} {2}", name, sex, age);
            Console.WriteLine("工作经历：{0}，{1}", work.WorkDate, work.company);
        }
       //克隆方法
        public Object Clone()
        {
            return (Object)this.MemberwiseClone();
        }
    }
    //客户端代码：
        class Program
    {
        static void Main(string[] args)
        {
           //定义一个简历类（原型类）
            Resume a = new Resume("大鸟");
            a.SetPersonalInfo("男", "29");
            a.SetWorkExperience("1998-2000", "XX公司");
 
 
            Resume b = (Resume)a.Clone();   //克隆一个a对象
            b.SetWorkExperience("1998-2006", "YY公司");  //重写b对象方法
            Resume c = (Resume)a.Clone();    //再次克隆一个a对象
            c.SetPersonalInfo("男", "24");   //重写c对象方法
            //显示
            a.Display();
            b.Display();
            c.Display();
 
            Console.Read();
        }
    }</span>

    重点在克隆方法MemberwiseClone()：如果字段是值类型的，则对该字段执行诸位复制，如果字段是引用类型，则复制引用不复制对象，因此，原始对象及其复本引用同一个对象，这叫浅复制，被复制对象的所有变量都含有与原来的对象相同的值，而所有的对其它对象的引用都仍然指向原来的对象。然而深复制是把引用的对象的变量指向复制过的新对象，而不是原有的被引用的对象。

深复制

<pre name="code" class="java">class WordExperience:ICloneable
    {
       private string workDate;
       public string WorkDate
       {
          get { return workDate; }
          set { workDate = value; }
       }
       private string company;
       public string company
       {
          get { return company; }
          set { company= value; }
       }
       //克隆方法
        public Object Clone()
        {
            return (Object)this.MemberwiseClone();
        }
    }
 
    //简历
    class Resume :ICloneable
    {
        private string name;
        private string sex;
        private string age;
        
        private WorkExperience work;
 
 
        public Resume(string name)
        {
            this.name = name;
            work = new WorkExperience();   //构造函数运行时，会在内存的堆中克隆出一个新的对象
        }

        pulbic Resume(WorkExperience work)
        {
            this.work=(WorkExperience)work.Clone();
        } 
        public void SetPersonalInfo(string sex, string age)
        {
            this.sex = sex;
            this.age = age;
        }
        //工作经历
        public void SetWorkExperience(string workDate, string company)
        {
            this.WorkDate = workDate;
            this.company = company;
        }
       //显示
        public void Display()
        {
            Console.WriteLine("{0} {1} {2}", name, sex, age);
            Console.WriteLine("工作经历：{0}，{1}", work.WorkDate, work.company);
        }

       //深复制克隆的实现。这个方法能克隆出简历类对象
       public Object Clone()
       {
            Resume obj = new Resume(this.work);//工作经验类具体克隆在构造函数里
            obj.name = this.name;
            obj.sex = this.sex;
            obj.age = this.age;
            return obj;
       }
    }

深浅复制内存分析简单对比：