Decouple an abstraction from its implementation so that the two can vary independently.(将抽象和实现解耦。使得倆者能够独立的变化)

public abstract class Product {
 public abstract void beProducted();
 public abstract void beSelled();
} 

公司抽象

public abstract class Corp {
 private Product product;
 
 public Corp(Product _product){
  this.product=_product;
 }
 
 public void makeMoney(){
  this.product.beProducted();
  this.product.beSelled();
 }
}

房子也是产品不是吗？

public class House extends Product {
 @Override
 public void beProducted() {
  System.out.println("生产出的房子是这种...");
 }
 @Override
 public void beSelled() {
  System.out.println("生产出的房子卖出去了....");
 }
}

public class IPod extends Product {
 @Override
 public void beProducted() {
  System.out.println("生产出的ipod是这种");
 }
 @Override
 public void beSelled() {
  System.out.println("生产的IPod卖出去了");
 }
}

public class HouseCorp extends Corp {
 public HouseCorp(House _house) {
  super(_house);
 }
 @Override
 public void makeMoney() {
  super.makeMoney();
  System.out.println("房地产公司赚大钱了");
 }
}

public class ShanZhaiCorp extends Corp {
 public ShanZhaiCorp(Product _product) {
  super(_product);
 }
 @Override
 public void makeMoney() {
  super.makeMoney();
  System.out.println("我是山寨，我赚钱呀");
 }
}

场景測试

public static void main(String[] args) {
  System.out.println("房地产公司是这样执行的");
  House house=new House();
  HouseCorp houseCorp=new HouseCorp(house);
  houseCorp.makeMoney();
 
  System.out.println();
 
  System.out.println("山寨公司是这样执行的");
  ShanZhaiCorp shanZhaiCorp=new ShanZhaiCorp(new IPod());
  shanZhaiCorp.makeMoney();
 }

瞧瞧人家山寨公司，什么东西流行就生产什么。反正价格低，质量嘛也有那么一点点保证。

我是菜鸟，我在路上。