参考：https://www.cnblogs.com/Kevin-ZhangCG/p/9088619.html

影子克隆也就是浅克隆

浅克隆

package com.pillar.test.clone.demo02.shallowcopy;

/**
 * @author Pillar
 * @version 1.0
 * @date 2022/9/14 19:36
 */
public class Teacher implements Cloneable {
    private String name;
    private Integer age;
    private Course course;

    public Teacher() {
    }

    public Teacher(String name, Integer age, Course course) {
        this.name = name;
        this.age = age;
        this.course = course;
    }

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public Course getCourse() {
        return course;
    }
    public void setCourse(Course course) {
        this.course = course;
    }

    @Override
    protected Teacher clone() throws CloneNotSupportedException {
        return (Teacher) super.clone();
    }
    @Override
    public String toString() {
        return "Teacher [name=" + name + ", age=" + age + ", course=" + course + "]";
    }
}

package com.pillar.test.clone.demo02.shallowcopy;

public class Course {
    
    private String name;
    private Integer id;

    public Course() {
    }

    public Course(String name, Integer id) {
        this.name = name;
        this.id = id;
    }

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    @Override
    public String toString() {
        return "Course [name=" + name + ", id=" + id + "]";
    }
    

}

package com.pillar.test.clone.demo02.shallowcopy;

/**
 * @author Pillar
 * @version 1.0
 * @date 2022/9/14 19:16
 */
/*
影子克隆
    调用clone方法产生的效果是：现在内存中开辟一块和原始对象一样的空间，然后拷贝原始对象中的内容
    但对于非基本类型，它们保存的仅仅是对象的引用
为了解决影子克隆所产生的问题，我们就需要使用深度克隆方案。
 */
public class TestClone {
    public static void main(String[] args) {
        Teacher teacher1 = new Teacher("zhangsan",18,new Course("语文",1));
        System.out.println("teacher1 ->" + teacher1);
        try {
            Teacher teacher2 = teacher1.clone();
            System.out.println("course是否相同: "+teacher1.getCourse().equals(teacher2.getCourse()));
            System.out.println("teacher2 ->" + teacher2);
            System.out.println(teacher1.equals(teacher2));
            System.out.println("Alter teacher2......");
            teacher2.setName("Lisi");
            teacher2.setAge(20);
            teacher2.getCourse().setName("English");
            teacher2.getCourse().setId(88);
            System.out.println("teacher1=>"+teacher1);
            System.out.println("teacher2=>"+teacher2);
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }
    }
}

深拷贝

package com.pillar.test.clone.demo02.deepcopy;


/**
 * @author Pillar
 * @version 1.0
 * @date 2022/9/14 19:36
 */
public class Teacher implements Cloneable {
    private String name;
    private Integer age;
    private Course course;

    public Teacher() {
    }

    public Teacher(String name, Integer age, Course course) {
        this.name = name;
        this.age = age;
        this.course = course;
    }

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public Course getCourse() {
        return course;
    }
    public void setCourse(Course course) {
        this.course = course;
    }

    @Override
    protected Object clone() throws CloneNotSupportedException {
        Teacher teacher = (Teacher)super.clone();
        teacher.course = course.clone();
        return teacher;
    }

    @Override
    public String toString() {
        return "Teacher [name=" + name + ", age=" + age + ", course=" + course + "]";
    }
}

package com.pillar.test.clone.demo02.deepcopy;

public class Course implements Cloneable{


    private String name;
    private Integer id;

    public Course() {
    }

    public Course(String name, Integer id) {
        this.name = name;
        this.id = id;
    }

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    @Override
    protected Course clone() throws CloneNotSupportedException {
        return (Course) super.clone();
    }
    @Override
    public String toString() {
        return "Course [name=" + name + ", id=" + id + "]";
    }
}

package com.pillar.test.clone.demo02.deepcopy;

/**
 * 测试clone方法
 * @author Kevin
 *
 */

public class TestClone {

    public static void main(String[] args){
        Teacher t1 = new Teacher();
        t1.setName("Kevin");
        t1.setAge(22);
        Course c1 = new Course();
        c1.setName("Math");
        c1.setId(66);
        t1.setCourse(c1);
        System.out.println("teacher1"+t1);

        try{
            Teacher t2 = (Teacher) t1.clone();
            System.out.println("Clone teacher2 from teacher1...");
            System.out.println("teacher2"+t2);
            System.out.println("Alter teacher2...");
            t2.setName("Ryan");
            t2.setAge(18);
            //修改courese属性
            t2.getCourse().setName("English");
            t2.getCourse().setId(88);
            System.out.println("teacher1"+t1);
            System.out.println("teacher2"+t2);
        }catch(CloneNotSupportedException e){
            e.printStackTrace();
        }
    }
}

浅拷贝拷贝了对象本身，但对于非基本类型，指向同一引用地址;
深拷贝拷贝了对象本身，也拷贝了引用对象