GOF23设计模式（五）

GOF设计模式之原型模式（prototype）

具有深克隆和浅克隆两种方法,使用原型模式需要继承Cloneable,原型模式一般用在需要new对象要耗费大量资源时使用。（反序列可以实现深克隆，本文章没有实现）

浅克隆

public class Sheep implements Cloneable{
	private String name;
	private Date birthday;
	@Override
	protected Object clone() throws CloneNotSupportedException {
		return super.clone();//Object的clone方法
	}
	public Sheep(String name, Date birthday) {
		this.name = name;
		this.birthday = birthday;
	}
	public String getName() {
		return name;
	}
	public Date getBirthday() {
		return birthday;
	}
	public Sheep() {
	}
	public void setName(String name) {
		this.name = name;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
}

测试

/**
 * 原型模式（浅克隆）共同使用对象
 *
 */
public class Client {
	public static void main(String[] args) throws CloneNotSupportedException {
		Date date=new Date(12345);
		Sheep s1 =new Sheep("张三",date);
		Sheep s2=(Sheep)s1.clone();
		System.out.println(s1.getBirthday());
		date.setTime(564321654);
		System.out.println("修改后"+s1.getBirthday());
		System.out.println(s2.getBirthday());
	}
}

结果

修改时间对象会影响克隆的对象
Thu Jan 01 08:00:12 CST 1970
修改后Wed Jan 07 20:45:21 CST 1970
Wed Jan 07 20:45:21 CST 1970

深克隆

public class Sheep implements Cloneable{
	private String name;
	private Date birthday;
	@Override
	protected Object clone() throws CloneNotSupportedException {
		Sheep s= (Sheep)super.clone();
		//深复制
		s.birthday=(Date) this.birthday.clone();//把属性也克隆
		return s;//返回s;
	}
	public Sheep(String name, Date birthday) {
		this.name = name;
		this.birthday = birthday;
	}
	public String getName() {
		return name;
	}
	public Date getBirthday() {
		return birthday;
	}
	public Sheep() {
	}
	public void setName(String name) {
		this.name = name;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
}

测试

/**
 * 原型模式（深克隆）克隆对象
 *
 */
public class Client {
	public static void main(String[] args) throws CloneNotSupportedException {
		Date date=new Date(12345);
		Sheep s1 =new Sheep("张三",date);
		Sheep s2=(Sheep)s1.clone();
		System.out.println(s1.getBirthday());
		date.setTime(564321654);
		System.out.println("修改后"+s1.getBirthday());
		System.out.println(s2.getBirthday());
	}
}

结果

修改时间对象不会影响克隆的对象
Thu Jan 01 08:00:12 CST 1970
修改后Wed Jan 07 20:45:21 CST 1970
Thu Jan 01 08:00:12 CST 1970