深克隆示例

• 为 birthday 单独写克隆代码；
• pig1 和 pig2 持有不同的 birthday；

import java.util.Date;

public class Pig implements Cloneable {

    private String name;
    private Date birthday;

    public Pig(String name, Date birthday) {
        this.name = name;
        this.birthday = birthday;
    }

    public String getName() {
        return name;
    }

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

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    protected Object clone() throws CloneNotSupportedException {
        Pig pig = (Pig)super.clone();

//        深克隆
        pig.birthday = (Date) pig.birthday.clone();
        return pig;
    }

    @Override
    public String toString() {
        return "Pig{" +
                "name='" + name + '\'' +
                ", birthday=" + birthday +
                '}' + super.toString().substring(super.toString().indexOf("@"));
    }

}

public class Test {
    public static void main(String[] args) throws CloneNotSupportedException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        Date birthday = new Date(0L);
        Pig pig1 = new Pig("佩奇",birthday);
        Pig pig2 = (Pig) pig1.clone();
        System.out.println(pig1);
        System.out.println(pig2);

        pig1.getBirthday().setTime(666666666666L);
        System.out.println();

        System.out.println(pig1);
        System.out.println(pig2);
    }
}

输出：

Pig{name='佩奇', birthday=Thu Jan 01 08:00:00 CST 1970}@7530d0a
Pig{name='佩奇', birthday=Thu Jan 01 08:00:00 CST 1970}@27bc2616

Pig{name='佩奇', birthday=Sat Feb 16 09:11:06 CST 1991}@7530d0a
Pig{name='佩奇', birthday=Thu Jan 01 08:00:00 CST 1970}@27bc2616