废话不多说,引出需求。
需求:建造房子,建造过程包括打地基、砌墙和封顶。房子各式各样,包括平房和别墅,编程模拟实现。
思路:定义房子类,包括建房的方法,然后定义平房和别墅继承房子类,重写相关方法。
类图:
代码:
public abstract class AbstractHouse {
public abstract void buildBasic();//打地基
public abstract void buildWalls();//砌墙
public abstract void buildRoof();//封顶
public void build() { //建房
buildBasic(); //三个步骤(注意顺序)
buildWalls();
buildRoof();
}
}
public class Bungalow extends AbstractHouse{
@Override
public void buildBasic() {
System.out.println("平房打地基");
}
@Override
public void buildWalls() {
System.out.println("平房砌墙");
}
@Override
public void buildRoof() {
System.out.println("平房封顶");
}
}
public class Villa extends AbstractHouse{
@Override
public void buildBasic() {
System.out.println("别墅打地基");
}
@Override
public void buildWalls() {
System.out.println("别墅砌墙");
}
@Override
public void buildRoof() {
System.out.println("别墅封顶");
}
}
public class Client {
public static void main(String[] args) {
Bungalow bungalow = new Bungalow();
bungalow.build();
Villa villa = new Villa();
villa.build();
}
}
运行结果:
缺点:
程序不好扩展和维护,把产品和创建产品过程封装在一起,耦合性高。
解耦产品和创建产品过程=》建造者模式
建造者模式(Builder Pattern)又叫生成器模式,是一种对象构建模式。它可以将复杂对象的建造过程抽象出来(抽象类别),使这个抽象过程的不同实现方法可以构造出不同表现(属性)的对象。
一步一步创建一个复杂的对象,允许用户只通过指定复杂对象的类型和内容就可以构建它们,而不需要知道内部的具体构建细节。
类图:
(
插播反爬信息)博主CSDN地址:https://wzlodq.blog.csdn.net/
代码:
public class House {
private String baise;
private String wall;
private String roof;
}
public abstract class HouseBuilder {
protected House house = new House();
//将建造的流程写好, 抽象的方法
public abstract void buildBasic();
public abstract void buildWalls();
public abstract void buildRoof();
//建造房子好, 将产品(房子) 返回
public House buildHouse() {
return house;
}
}
3.Bungalow类(ConcreteBuilder具体建造者A)
public class Bungalow extends HouseBuilder {
@Override
public void buildBasic() {
System.out.println("平房打地基");
}
@Override
public void buildWalls() {
System.out.println("平房砌墙");
}
@Override
public void buildRoof() {
System.out.println("平房封顶");
}
}
4.Villa类(ConcreteBuilder具体建造者B)
public class Villa extends HouseBuilder {
@Override
public void buildBasic() {
System.out.println("别墅打地基");
}
@Override
public void buildWalls() {
System.out.println("别墅砌墙");
}
@Override
public void buildRoof() {
System.out.println("别墅封顶");
}
}
5.HouseDirector类(Director指挥者)
public class HouseDirector {
HouseBuilder houseBuilder = null;
//构造器传入 houseBuilder
public HouseDirector(HouseBuilder houseBuilder) {
this.houseBuilder = houseBuilder;
}
//通过setter 传入 houseBuilder
public void setHouseBuilder(HouseBuilder houseBuilder) {
this.houseBuilder = houseBuilder;
}
//如何处理建造房子的流程,交给指挥者
public House constructHouse() {
houseBuilder.buildBasic();
houseBuilder.buildWalls();
houseBuilder.buildRoof();
return houseBuilder.buildHouse();
}
}
public class Client {
public static void main(String[] args) {
//盖平房
Bungalow commonHouse = new Bungalow();
//准备创建房子的指挥者
HouseDirector houseDirector = new HouseDirector(commonHouse);
//完成盖房子,返回产品(普通房子)
House house = houseDirector.constructHouse();
System.out.println("--------------------------");
//盖别墅
Villa highBuilding = new Villa();
//重置建造者
houseDirector.setHouseBuilder(highBuilding);
//完成盖房子,返回产品(高楼)
houseDirector.constructHouse();
}
}
运行结果: