原型模式(prototype)
意图: 用原型实例指定创建对象的种类，并通过拷贝这些原型创建新的对象。
结构图
实现示例：
原型Prototype:
public class Client {private Prototype prototype;public void setPrototype(Prototype prototype) {this.prototype = prototype;}public void runExample() throws Exception {Container c = new Container();ConcretePrototype1 item1 = null;item1 = (ConcretePrototype1)prototype.clone();item1.setDescription("this is item1");c.addItem(item1);ConcretePrototype1 item2 = null;item2 = (ConcretePrototype1)item1.clone();item2.setDescription("This is item2");c.addItem(item2);ConcretePrototype2 item3 = null;item3 = new ConcretePrototype2();item3.setFlag(100);c.addItem(item3);ConcretePrototype2 item4 = null;item4 = (ConcretePrototype2)item3.clone();item4.setFlag(500);c.addItem(item4);}public static void main(String args[]) throws Exception {Client client = new Client();client.setPrototype(new ConcretePrototype1());client.runExample();}}
执行结果：
Now items list:
Concrete 1 description: this is item1
Now items list:
Concrete 1 description: this is item1
Concrete 1 description: This is item2
Now items list:
Concrete 1 description: this is item1
Concrete 1 description: This is item2
Concrete 2 flag = 100
Now items list:
Concrete 1 description: this is item1
Concrete 1 description: This is item2
Concrete 2 flag = 100
Concrete 2 flag = 500
注：示例中原型Prototype只有一个属性，通过复制来创建没有体现其优势，当prototype中属性较多时，通过复制可以节省初始化的开销
