浅拷贝和深拷贝

最新推荐文章于 2022-01-29 13:53:53 发布

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本文深入探讨Java中对象的深拷贝与浅拷贝概念，通过实例代码演示了如何实现对象的深拷贝，特别是在包含引用类型成员变量的情况下。文章详细解释了深拷贝与浅拷贝的区别，以及实现深拷贝时需要注意的问题。

Father

package com.kevin.test.test;

/**
 * Created by jinyugai on 2018/11/16.
 */
public class Father implements Cloneable {
    public String xm;
    public Child child;
    public Girl girl;
    public Father(Child child,Girl girl) {
        this.child = child;
        this.girl = girl;
    }


    @Override
    protected Object clone() throws CloneNotSupportedException {
        Father father = (Father)super.clone();
        father.girl = (Girl)girl.clone();
        return father;
    }
}

Child

package com.kevin.test.test;

/**
 * Created by jinyugai on 2018/11/16.
 */
public final class Child {
    public String name;
}

Girl

package com.kevin.test.test;

/**
 * Created by jinyugai on 2018/11/16.
 */
public class Girl implements Cloneable {
    public String name;


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

测试

package com.kevin.test.test;

/**
 * Created by jinyugai on 2018/11/16.
 */
public class CloneTest {
    public static void main(String[] args) {
        Father father1 = new Father(new Child(),new Girl());
        father1.xm = "Kevin";
        father1.child.name = "youyou";
        father1.girl.name = "toto";
        try {
            //浅拷贝
            // child类虽然声明为final修饰，但是child并没有被重新new 没有重新划分内存
            //深拷貝
            // girl类深拷贝
            Father father2 = (Father)father1.clone();
            father2.xm = "kevin2";
            father2.child.name = "youyou2";
            father1.girl.name = "toto2";
            System.out.println("打印fathe ===========");
            System.out.println("打印fathe1 ："+father1.xm);
            System.out.println("打印fathe2 ：" + father2.xm);
            System.out.println("打印child.name ===========");
            System.out.println("打印fathe1 child.name:"+father1.child.name);
            System.out.println("打印fathe2 child.name:"+father2.child.name);
            System.out.println("打印girl.name ===========");
            System.out.println("打印fathe1 girl.name:"+father1.girl.name);
            System.out.println("打印fathe2 girl.name:"+father2.girl.name);
            System.out.println("对比是否指向同一个引用 ===========");
            System.out.println(father1.xm == father2.xm);
            System.out.println(father1.child == father2.child);
            System.out.println(father1.girl == father2.girl);



        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }

    }
}

结果--浅拷贝--直接复制的是属性对象的地址，没有new一个新的

打印fathe ===========
打印fathe1 ：Kevin
打印fathe2 ：kevin2
打印child.name ===========
打印fathe1 child.name:youyou2
打印fathe2 child.name:youyou2
打印girl.name ===========
打印fathe1 girl.name:toto2
打印fathe2 girl.name:toto
对比是否指向同一个引用 ===========
false
true
false