Java深拷貝和淺拷貝的區別

本文部分內容參考自：https://www.cnblogs.com/lgxblog/p/11568153.html 

淺拷貝：被拷貝（複製）的對象的所有的屬性都與原對象有相同的值，且所有的對象引用仍然指向原來的對象。 

package com.design.clone;

public class Experience implements Cloneable{

    private String skill;

    public void setSkill(String skill) {
        this.skill = skill;
    }

    @Override
    public String toString() {
        return "Experience{" +
                "skill='" + skill + '\'' +
                '}';
    }
}

package com.design.clone;

public class ExperienceClone implements Cloneable {

    private int age;

    private Experience experience;

    public ExperienceClone() {
        this.age = 10;
        this.experience = new Experience();
    }

    public void setSkill(String skill) {
        experience.setSkill(skill);
    }

    public void show() {
        System.out.println(experience.toString());
    }

    public int getAge() {
        return age;
    }

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

package com.design.clone;

public class Test {
    public static void main(String[] args) throws CloneNotSupportedException {
        ExperienceClone experienceClone = new ExperienceClone();
        experienceClone.setSkill("我是小明，我精通Java、C++的複製黏貼");
        experienceClone.show();
        ExperienceClone experienceClone1 = (ExperienceClone) experienceClone.clone();
        experienceClone1.show();
        experienceClone1.setSkill("我是小明的副本，我精通Java、C++");
        experienceClone1.show();
        experienceClone.show();
        System.out.println(experienceClone1.getAge());
    }
}

控制檯輸出結果： 

Experience{skill='我是小明，我精通Java、C++的複製黏貼'}
Experience{skill='我是小明，我精通Java、C++的複製黏貼'}
Experience{skill='我是小明的副本，我精通Java、C++'}
Experience{skill='我是小明的副本，我精通Java、C++'}
10

深拷貝： 除了拷貝（複製）所有的屬性外，對於對象屬性，會複製一份對象引用並指向一個新的對象上。

 

package com.design.clone;

public class Experience implements Cloneable{

    private String skill;

    public void setSkill(String skill) {
        this.skill = skill;
    }

    @Override
    public String toString() {
        return "Experience{" +
                "skill='" + skill + '\'' +
                '}';
    }

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

package com.design.clone;

public class ExperienceClone implements Cloneable {

    private int age;

    private Experience experience;

    public ExperienceClone() {
        this.age = 10;
        this.experience = new Experience();
    }

    public void setSkill(String skill) {
        experience.setSkill(skill);
    }

    public void show() {
        System.out.println(experience.toString());
    }

    public int getAge() {
        return age;
    }

    @Override
    public ExperienceClone clone() {
        ExperienceClone experienceClone = null;
        try {
            experienceClone = (ExperienceClone)super.clone();
            experienceClone.experience = (Experience)this.experience.clone();
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
        return experienceClone;
    }
}

package com.design.clone;

public class Test {
    public static void main(String[] args) throws CloneNotSupportedException {
        ExperienceClone experienceClone = new ExperienceClone();
        experienceClone.setSkill("我是小明，我精通Java、C++的複製黏貼");
        experienceClone.show();
        ExperienceClone experienceClone1 = (ExperienceClone) experienceClone.clone();
        experienceClone1.show();
        experienceClone1.setSkill("我是小明的副本，我精通Java、C++");
        experienceClone1.show();
        experienceClone.show();
        System.out.println(experienceClone1.getAge());
    }
}

控制檯輸出結果： 

Experience{skill='我是小明，我精通Java、C++的複製黏貼'}
Experience{skill='我是小明，我精通Java、C++的複製黏貼'}
Experience{skill='我是小明的副本，我精通Java、C++'}
Experience{skill='我是小明，我精通Java、C++的複製黏貼'}
10

知識擴展：我們常用的設計模式——原型設計模式便是使用深拷貝。