Java基础 深拷贝浅拷贝

• 非基本数据类型 需要new新空间

class Student implements Cloneable{

    private int id;

    private String name;

    private Vector course;

    public Student(){

        try{

            Thread.sleep(1000);

            System.out.println("Student Constructor called.");

        }catch (InterruptedException e){

            e.printStackTrace();

        }

    }

    public String getName() {return name;}

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

    public int getId() {return id;}

    public void setId(int id) {this.id = id;}

    public Vector getCourse() {return course;}

    public void setCourse(Vector course) {this.course = course;}

    //浅拷贝

    public Student newInstance(){

        try{

            return (Student)this.clone();

        }catch (CloneNotSupportedException e){

            e.printStackTrace();

        }

        return null;

    }

    //深拷贝

    public Student deepClone(){

        try{

            Student cloning = (Student) super.clone();

            cloning.course = new Vector();

            return cloning;

        }catch (CloneNotSupportedException e){

            e.printStackTrace();

        }

        return null;

    }

}

public Object clone(){      //覆写clone()，深拷贝

    try{

        Student cloning = (Student) super.clone();

        // 这里不能使用Student cloning = (Student) this.clone()的原因:

        正在覆写本类的clone()方法，如果再调用本类的函数，即：this.clone()，就相当于无限递归无限死循环了，最终会崩溃的。所以这里：super.clone()。

        cloning.courses = new Vector();     //关键点：非基本数据类型的空间需要自己新开辟一块儿

        return cloning;

    }catch(CloneNotSupportedException e){

        e.printStackTrace();

    }

    return null;

}  

参考资料

谨慎覆盖clone

Java中的clone() 深拷贝 浅拷贝