克隆模式

克隆模式

浅克隆：创建一个新对象，新对象的属性和原来对象完全相同，对于非基本类型属性，仍指向原有属性所指向的对象的内存地址。

深克隆：创建一个新对象，属性中引用的其他对象也会被克隆，不再指向原有对象地址。

创建原型类Monkey

import java.util.Date;
public class Monkey {
    public int height;
    public int weight;
    public Date birthday;
}

创建引用对象JinGuBang

import java.io.Serializable;

/**
 * @author Yin
 * @date 2021/3/4 20:12
 */
public class JinGuBang implements Serializable {
    public float h = 100;
    public float d = 100;
    
    public void big() {
        this.d *= 2;
        this.h *= 2;
    }
    public void small(){
        this.d /= 2;
        this.h /= 2;
    }
}

创建具体的对象类QiTianDaSheng

import java.io.*;
import java.util.Date;

/**
 * @author Yin
 * @date 2021/3/4 20:15
 */
public class QiTianDaSheng extends Monkey implements Cloneable, Serializable {
    public JinGuBang jinGuBang;
    
    public QiTianDaSheng() {
        this.birthday = new Date();
        this.jinGuBang = new JinGuBang();
    }
    
    @Override
    protected Object clone() throws CloneNotSupportedException {
        return this.deepClone();
    }
    
    public Object deepClone() {
        try {
            // 将对象写到流里
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ObjectOutputStream oos = new ObjectOutputStream(bos);
            oos.writeObject(this);
            // 从流里读出来
            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.weight;
        
        qiTianDaSheng.jinGuBang = target.jinGuBang;
        qiTianDaSheng.birthday = new Date();
        
        return qiTianDaSheng;
    }
}

测试代码

/**
 * @author Yin
 * @date 2021/3/4 20:42
 */
public class DeepCloneTest {
    public static void main(String[] args) {
        QiTianDaSheng qiTianDaSheng = new QiTianDaSheng();
        
        try {
            QiTianDaSheng clone = (QiTianDaSheng) qiTianDaSheng.clone();
            System.out.println(clone.birthday);
            System.out.println(qiTianDaSheng.birthday);
            System.out.println(clone.birthday == qiTianDaSheng.birthday);
            System.out.println("深克隆: " + (qiTianDaSheng.jinGuBang == clone.jinGuBang));
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        
        QiTianDaSheng q = new QiTianDaSheng();
        QiTianDaSheng n = q.shallowClone(q);
        System.out.println("浅克隆: " + (q.jinGuBang == n.jinGuBang));
    }
}

测试结果：

参考文章链接：https://www.cnblogs.com/liqiangchn/p/9465186.html

参考书籍：《Spring 5核心原理与30个类手写实战》