原型模式必知必会

ゝ一纸荒年。 2023-03-13 09:21 2阅读 0赞

### 文章目录 ###

*  类图
 *  实例
 *  深克隆
 *  深克隆破坏单例解决方式
 *  个人理解
 *  原型克隆和new的区别
 *  原型模式和抽象工厂模式的区别
 *  本质
 *  代码地址:

# 类图 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JhaWR1XzIxMzQ5NjM1_size_16_color_FFFFFF_t_70]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JhaWR1XzIxMzQ5NjM1_size_16_color_FFFFFF_t_70 1]

# 实例 #

public interface Prototype{ 
        Prototype clone();
    }

public class ConcretePrototypeA implements Prototype { 
    
        private int age;
        private String name;
        private List hobbies;
    
        public int getAge() { 
            return age;
        }
    
        public void setAge(int age) { 
            this.age = age;
        }
    
        public String getName() { 
            return name;
        }
    
        public void setName(String name) { 
            this.name = name;
        }
    
        public List getHobbies() { 
            return hobbies;
        }
    
        public void setHobbies(List hobbies) { 
            this.hobbies = hobbies;
        }
    
        @Override
        public ConcretePrototypeA clone() { 
            ConcretePrototypeA concretePrototype = new ConcretePrototypeA();
            concretePrototype.setAge(this.age);
            concretePrototype.setName(this.name);
            concretePrototype.setHobbies(this.hobbies);
            return concretePrototype;
        }
    
    }

public class ConcretePrototypeB implements Prototype { 
    
        @Override
        public Prototype clone() { 
            return null;
        }
    }

public class Client { 
    
        private Prototype prototype;
    
        public Client(Prototype prototype){ 
            this.prototype = prototype;
        }
        public Prototype startClone(Prototype concretePrototype){ 
            return (Prototype)concretePrototype.clone();
        }
    
    }

public class PrototypeTest { 
    
        public static void main(String[] args) { 
    
            // 创建一个具体的需要克隆的对象
            ConcretePrototypeA concretePrototype = new ConcretePrototypeA();
            // 填充属性，方便测试
            concretePrototype.setAge(18);
            concretePrototype.setName("prototype");
            List hobbies = new ArrayList<String>();
            concretePrototype.setHobbies(hobbies);
            System.out.println(concretePrototype);
    
            // 创建Client对象，准备开始克隆
            Client client = new Client(concretePrototype);
            ConcretePrototypeA concretePrototypeClone = (ConcretePrototypeA) client.startClone(concretePrototype);
            System.out.println(concretePrototypeClone);
    
            System.out.println("克隆对象中的引用类型地址值：" + concretePrototypeClone.getHobbies());
            System.out.println("原对象中的引用类型地址值：" + concretePrototype.getHobbies());
            System.out.println("对象地址比较："+(concretePrototypeClone.getHobbies() == concretePrototype.getHobbies()));
    
    
        }
    }

![在这里插入图片描述][20200512215413190.png]

# 深克隆 #

例子:  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JhaWR1XzIxMzQ5NjM1_size_16_color_FFFFFF_t_70 2]

public class Monkey { 
        public int height;
        public int weight;
        public Date birthday;
    }

public class JinGuBang implements Serializable { 
        public float h = 100;
        public float d = 10;
    
        public void big(){ 
            this.d *= 2;
            this.h *= 2;
        }
    
        public void small(){ 
            this.d /= 2;
            this.h /= 2;
        }
    }

public class QiTianDaSheng extends Monkey implements Cloneable,Serializable { 
    
        public JinGuBang jinGuBang;
    
        public  QiTianDaSheng(){ 
            //只是初始化
            this.birthday = new Date();
            this.jinGuBang = new JinGuBang();
        }
    
        @Override
        protected Object clone() throws CloneNotSupportedException { 
            return this.deepClone();
        }
    
    
        //深克隆
        public Object deepClone(){ 
            try{ 
    
                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                ObjectOutputStream oos = new ObjectOutputStream(bos);
                oos.writeObject(this);
    
                ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
                ObjectInputStream ois = new ObjectInputStream(bis);
    
                QiTianDaSheng copy = (QiTianDaSheng)ois.readObject();
                copy.birthday = new Date();
                return copy;
    
            }catch (Exception e){ 
                e.printStackTrace();
                return null;
            }
    
        }
    
    
        public QiTianDaSheng shallowClone(QiTianDaSheng target){ 
    
            QiTianDaSheng qiTianDaSheng = new QiTianDaSheng();
            qiTianDaSheng.height = target.height;
            qiTianDaSheng.weight = target.height;
    
            qiTianDaSheng.jinGuBang = target.jinGuBang;
            qiTianDaSheng.birthday = new Date();
            return  qiTianDaSheng;
        }
    
        //浅克隆
        public QiTianDaSheng deep2(QiTianDaSheng target){ 
    
            QiTianDaSheng qiTianDaSheng = new QiTianDaSheng();
            qiTianDaSheng.height = target.height;
            qiTianDaSheng.weight = target.height;
    
            qiTianDaSheng.jinGuBang =  target.jinGuBang;
            qiTianDaSheng.birthday = new Date();
            return  qiTianDaSheng;
        }
    
    }

public class DeepCloneTest { 
    
        public static void main(String[] args) { 
    
            QiTianDaSheng qiTianDaSheng = new QiTianDaSheng();
            try { 
                QiTianDaSheng clone = (QiTianDaSheng)qiTianDaSheng.clone();
                System.out.println("深克隆：" + (qiTianDaSheng.jinGuBang == clone.jinGuBang));
            } catch (Exception e) { 
                e.printStackTrace();
            }
    
            QiTianDaSheng q = new QiTianDaSheng();
            QiTianDaSheng n = q.shallowClone(q);
            System.out.println("浅克隆：" + (q.jinGuBang == n.jinGuBang));
    
    
        }
    }

![在这里插入图片描述][20200512220143418.png]

# 深克隆破坏单例解决方式 #

要么你我们的单例类不实现Cloneable接口；  
要么我们重写clone()方法，在clone方法中返回单例对象即可，具体代码如下：

@Override
    protected Object clone() throws CloneNotSupportedException{ 
    	return INSTANCE;
    }

Cloneable源码分析先看我们常用的ArrayList就实现了Cloneable接口，来看代码clone()方法的实现：\`

public Object clone(){ 
    	try{ 
    		ArrayList<?>v=(ArrayList<?>)
    		super.clone();v.elementData=Arrays.copyOf(elementData,size);
    	     v.modCount=0;
    	     return v;
    	}catch(CloneNotSupportedExceptione){ 
    		。。。
    	}

# 个人理解 #

感觉和之前new出来一个对象，再set值一样，只是，这个set的功能在对象内部。对外只暴露一个clone或者其他自定义接口。

# 原型克隆和new的区别 #

![在这里插入图片描述][20200512220323255.png]

# 原型模式和抽象工厂模式的区别 #

![在这里插入图片描述][20200512220432199.png]

# 本质 #

**`本质: 克隆生成对象。`**

--------------------

# 代码地址: #

[https://github.com/hufanglei/pattern-learn/tree/master/src/main/java/com/example/prototype][https_github.com_hufanglei_pattern-learn_tree_master_src_main_java_com_example_prototype]  
笔记地址 [https://blog.csdn.net/baidu\_21349635/article/details/106086578][https_blog.csdn.net_baidu_21349635_article_details_106086578]

--------------------

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不定时推送相关文章，期待和大家一起成长！！  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JhaWR1XzIxMzQ5NjM1_size_16_color_FFFFFF_t_70 3]

--------------------

完

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JhaWR1XzIxMzQ5NjM1_size_16_color_FFFFFF_t_70 1]: /images/20230312/3fe1daf2b579442dbea501db6e98dbb8.png
[20200512215413190.png]: https://img-blog.csdnimg.cn/20200512215413190.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JhaWR1XzIxMzQ5NjM1_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20200512215621222.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JhaWR1XzIxMzQ5NjM1,size_16,color_FFFFFF,t_70
[20200512220143418.png]: https://img-blog.csdnimg.cn/20200512220143418.png
[20200512220323255.png]: https://img-blog.csdnimg.cn/20200512220323255.png
[20200512220432199.png]: https://img-blog.csdnimg.cn/20200512220432199.png
[https_github.com_hufanglei_pattern-learn_tree_master_src_main_java_com_example_prototype]: https://github.com/hufanglei/pattern-learn/tree/master/src/main/java/com/example/prototype
[https_blog.csdn.net_baidu_21349635_article_details_106086578]: https://blog.csdn.net/baidu_21349635/article/details/106086578
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JhaWR1XzIxMzQ5NjM1_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20200524195802340.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JhaWR1XzIxMzQ5NjM1,size_16,color_FFFFFF,t_70