Java深克隆与浅克隆

浅拷贝

Otherwise, this method creates a new instance of the class of this object and initializes all its fields with exactly the contents of the corresponding fields of this object, as if by assignment; the contents of the fields are not themselves cloned.

Object类的clone方法将基于该类的对象创建一个新的实例，并且使用该对象中的所有字段初始化新实例中的字段，就像赋值操作样；字段的内容本身不会被克隆。
以下面这段代码举例，首先实例化了一个对象s，然后使用使用该对象克隆出一个新的对象s2，s和s2是两个不同的对象，但是对象中的字段是通过赋值实现的，这样的话就意味着对象s和对象s2中的name值指向同一块内存地址。

@Data
class Student implements Cloneable {
    private String name;
    private int age;
    @Override
    protected Student clone() throws CloneNotSupportedException {
        return (Student) super.clone();
    }
}

public class ShallowCopy {
    public static void main(String[] args) throws CloneNotSupportedException {
        Student s = new Student();
        s.setAge(12);
        s.setName("yinglv");
        Student s2 = s.clone();
        System.out.println(s==s2);//false
        System.out.println(s2.getName() == s.getName());//true
    }
}

深拷贝

深拷贝跟浅拷贝不同的一点在于，新对象的属性指向不同的地址空间，深拷贝可以通过序列化的方式实现。

    public Student cloneObject() throws IOException, ClassNotFoundException {
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        ObjectOutputStream objectOutputStream = new ObjectOutputStream(outputStream);
        objectOutputStream.writeObject(this);
        ByteArrayInputStream inputStream = new ByteArrayInputStream(outputStream.toByteArray());
        ObjectInputStream objectInputStream = new ObjectInputStream(inputStream);
        return (Student) objectInputStream.readObject();
    }

参考文献

[1]https://www.cnblogs.com/qlwang/p/7889802.html