原型模式介绍

原型模式，是指将一个对象，完整的克隆出一份 实现Cloneable接口，调用clone()方法 应用场景：

• spring bean：单例模式+原型模式
• 工厂模式： new 对象 <–替换成–> 原型模式

代码实现案例

/**
 * 浅克隆：将对象的值完全拷贝一份，
 * 		如果属性为引用类型变量，则拷贝属性指向的内存地址
 * 实现Cloneable接口
 * 重写 clone 方法（不做改造）
 */
public class Student implements Cloneable{
    public int id;
    public Integer age;
    public String name;
    public Date createTime;

    public Student(int id, Integer age, String name,Date createTime) {
        this.id = id;
        this.age = age;
        this.name = name;
        this.createTime = createTime;
    }

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

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

    public static void main(String[] args) throws Exception {
        Student stu_1 = new Student(1,18,"小红",new Date());
        Student stu_2 = (Student) stu_1.clone();
        System.out.println(stu_1);
        System.out.println(stu_2);

        System.out.println("-------修改stu_2的值------");
        stu_2.id = 2;       //不影响原对象
        stu_2.age = 20;    //不影响原对象
        stu_2.name = "小兰";//不影响原对象
        // ------- 影响原对象 -------
        stu_2.createTime.setTime(22123156);
        System.out.println(stu_1);
        System.out.println(stu_2);
    }
}
输出结果为：
    Student{id=1, age=18, name='小红', createTime=Sun Apr 24 12:39:28 CST 2022}
Student{id=1, age=18, name='小红', createTime=Sun Apr 24 12:39:28 CST 2022}
-------修改stu_2的值------
    Student{id=1, age=18, name='小红', createTime=Thu Jan 01 14:08:43 CST 1970}
Student{id=2, age=20, name='小兰', createTime=Thu Jan 01 14:08:43 CST 1970}


/**
* 实现深克隆的方式：
*  1.序列化与反序列化
*  2.改造clone方法
*/
@Override
protected Object clone() throws CloneNotSupportedException {
    Student stu = (Student) super.clone();
    //将引用类型的变量，也克隆一份
    stu.createTime = (Date) this.createTime.clone();
    return stu;
}
输出结果为：
    Student{id=1, age=18, name='小红', createTime=Sun Apr 24 12:39:28 CST 2022}
Student{id=1, age=18, name='小红', createTime=Sun Apr 24 12:39:28 CST 2022}
-------修改stu_2的值------
    Student{id=1, age=18, name='小红', createTime=Sun Apr 24 12:39:28 CST 2022}
Student{id=2, age=20, name='小兰', createTime=Thu Jan 01 14:08:43 CST 1970}