工厂方法(Factory mothod Pattern
工厂方法(Factory mothod Pattern)
工厂模式:定义一个用于创建对象的接口,让子类决定实例化哪一个类。工厂方法使一个类的实例化延迟到其子类。
代码:
Product.java产品抽象类
package org.factoryMethod.lazy;import java.util.HashMap;public class ProductFactory{private static final HashMap<String, Product> pool = new HashMap<String, Product>();private static synchronized Product createProduct(String key){Product product = null;//如果Map中已有对象if(pool.containsKey(key)){product = pool.get(key);}else{if(key.equals("ConcreteProduct1")){product = new ConcreteProduct1();}else{product = new ConcreteProduct2();}pool.put(key, product);}return product;}}