java八股文面试[java基础]——浅拷贝和深拷贝

news2025/1/12 13:38:31

自验证：创建Class Student两个类， Student中含有Class对象

public class Class implements Cloneable {
    public String getName() {
        return name;
    }

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

    private String name;

    public Class(String name) {
        this.name = name;
    }

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

public class Student implements Cloneable {
    public String getName() {
        return name;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Class getClazz() {
        return clazz;
    }

    public void setClazz(Class clazz) {
        this.clazz = clazz;
    }

    private String name;
    private int age;
    private Class clazz;

    public Student(String name, int age, Class clazz) {
        this.name = name;
        this.age = age;
        this.clazz = clazz;
    }

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

测试代码：

public class Copy {
    public static void main(String[] args) throws CloneNotSupportedException {
        Class clazz = new Class("一班");
        Student student = new Student("张三", 18, clazz);
        Student newStudent = (Student) student.clone();
        student.getClazz().setName("二班");

        System.out.println("=== student===");
        System.out.println(student);
        System.out.println(student.getName());
        System.out.println(student.getAge());
        System.out.println(student.getClazz());
        System.out.println(student.getClazz().getName());

        System.out.println("=== newStudent===");
        System.out.println(newStudent);
        System.out.println(newStudent.getName());
        System.out.println(newStudent.getAge());
        System.out.println(newStudent.getClazz());
        System.out.println(newStudent.getClazz().getName());

    }
}

输出：

可以看到不同的Student对象，但是有相同的Class对象

修改Student clone方法：

@Override
    protected Object clone() throws CloneNotSupportedException {
        Student student = (Student) super.clone();
        student.setClazz((Class) clazz.clone());
        return student;
    }

可以看到不同的class对象，不同的值：