builder 模式中：

/*

* A test client to create a house

* but we do not know how the room and door be created

*/

public class TestClient {

public TestClient() {

}

public static void main(String[] args) {

House myHouse = new House(); ----我认为这行是多余，使人误解。应该修改为： House myHouse ；当然即使不修改，也没有任何错，除了浪费内存。

ConcreteHouseBuilderA myHouseBuilder = new ConcreteHouseBuilderA();

HouseDirector myHouseDirector = new HouseDirector();

myHouseDirector.CreateHouse(myHouseBuilder);

myHouse = myHouseBuilder.getHouse();

System.out.println("My house has room :" + myHouse.getRoomNumber());

System.out.println("My house has door :" + myHouse.getDoorNumber());

}

}