实现两个类分别为student和address

class Student implements Cloneable{
    private String name;
    private Address address;

    public Student(String name, Address address) {
        this.name = name;
        this.address = address;
    }

    @Override
    public String toString() {
        return "Student{" +
               "name='" + name + '\'' +
               ", address=" + address +
               '}';
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }
}

class Address implements Cloneable {
    private String address;

    public Address(String address) {
        this.address = address;
    }

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

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

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

1. 浅克隆

1.1 利用Object的clone方法

public class Main {
    public static void main(String[] args) throws Exception {
        Address address = new Address("beijing");
        Student student = new Student("zhangsan", address);
        Student clone = (Student) student.clone();

        System.out.println(student.toString());
        System.out.println(clone.toString());

        address.setAddress("shanghai");

        System.out.println(student.toString());
        System.out.println(clone.toString());

    }
}
------------------------------结果--------------------------------
Student{name='zhangsan', address=Address{address='beijing'}}
Student{name='zhangsan', address=Address{address='beijing'}}
Student{name='zhangsan', address=Address{address='shanghai'}}
Student{name='zhangsan', address=Address{address='shanghai'}}

2. 深克隆

2.1 重写clone方法

重写clone方法要求所有用到的引用类型都要重写

class Student implements Cloneable{
    // ...

    @Override
    protected Object clone() throws CloneNotSupportedException {
        // 克隆基本对象
        Student clone = (Student) super.clone();

        // 深克隆Address对象
        // 克隆一个新的Address对象, 要求Address类如果有引用类型也要重写clone方法
        // 利用递归的思想克隆所有的基本类型
        clone.address = (Address) this.address.clone();
        return clone;
    }
    // ...
}

class Address implements Cloneable {
    // ...

    @Override
    protected Object clone() throws CloneNotSupportedException {
        // 由于Address类只有基本类型可以直接调用Object中的clone方法
        return super.clone();
    }

    // ...
}

测试结果

------------------------结果-------------------------------------
Student{name='zhangsan', address=Address{address='beijing'}}
Student{name='zhangsan', address=Address{address='beijing'}}
Student{name='zhangsan', address=Address{address='shanghai'}}
Student{name='zhangsan', address=Address{address='beijing'}}

2.2 序列化

class Student implements Serializable {
    // ...

    // 先写再读
    public Student deepClone() throws Exception{
        // 1. 创建一个 ByteArrayOutputStream，用于存储对象的字节流
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

        // 2. 创建 ObjectOutputStream，将对象序列化为字节流
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);

        // 3. 将当前对象序列化到字节流中
        objectOutputStream.writeObject(this);
        objectOutputStream.flush(); // 刷新流，确保所有字节都写入

        // 4. 创建一个 ByteArrayInputStream，读取字节流并将其转化为对象
        ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());

        // 5. 创建 ObjectInputStream，从字节流中反序列化出对象
        ObjectInputStream objectInputStream = new ObjectInputStream(byteArrayInputStream);

        // 6. 从字节流中反序列化出一个新的对象，并返回这个对象
        return (Student) objectInputStream.readObject();
    }

    //@Override
    //protected Object clone() throws CloneNotSupportedException {
    //    // 克隆基本数据类型
    //    Student clone = (Student) super.clone();
    //
    //    // 深克隆Address对象
    //    // 克隆一个新的Address对象, 要求Address类如果有引用类型也要重写clone方法
    //    // 利用递归的思想克隆所有的基本类型
    //    clone.address = (Address) this.address.clone();
    //    return clone;
    //}

    // ...
}

class Address implements Serializable {
    // ...
}

测试结果

-----------------------------结果-----------------------------------
Student{name='zhangsan', address=Address{address='beijing'}}
Student{name='zhangsan', address=Address{address='beijing'}}
Student{name='zhangsan', address=Address{address='shanghai'}}
Student{name='zhangsan', address=Address{address='beijing'}}