设计模式(12) -- 建造者模式

文章目录

• ​​需求​​

• ​​传统写法​​
• ​​优缺点​​

• ​​建造者模式​​

• ​​介绍​​
• ​​建 造者模式的四个角 色​​
• ​​改进方案类图​​
• ​​代码​​

• ​​类似建造者模式的jdk源码​​
• ​​总结​​
• ​​源码地址​​

需求

传统写法

AbstractHouse

public abstract class AbstractHouse {

//打地基
public abstract void buildBasic();
//砌墙
public abstract void buildWalls();
//封顶
public abstract void roofed();

public void build() {
buildBasic();
buildWalls();
roofed();
}

}

CommonHouse

public class CommonHouse extends AbstractHouse {

@Override
public void buildBasic() {
// TODO Auto-generated method stub
System.out.println(" 普通房子打地基 ");
}

@Override
public void buildWalls() {
// TODO Auto-generated method stub
System.out.println(" 普通房子砌墙 ");
}

@Override
public void roofed() {
// TODO Auto-generated method stub
System.out.println(" 普通房子封顶 ");
}

}

测试

public class Client {

public static void main(String[] args) {
// TODO Auto-generated method stub
CommonHouse commonHouse = new CommonHouse();
commonHouse.build();
}

}

优缺点

建造者模式

介绍

建 造者模式的四个角 色

改进方案类图

代码

House

//产品->Product
public class House {
private String baise;
private String wall;
private String roofed;
public String getBaise() {
return baise;
}
public void setBaise(String baise) {
this.baise = baise;
}
public String getWall() {
return wall;
}
public void setWall(String wall) {
this.wall = wall;
}
public String getRoofed() {
return roofed;
}
public void setRoofed(String roofed) {
this.roofed = roofed;
}
}

HouseBuilder

// 抽象的建造者
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 roofed();

//建造房子好， 将产品(房子) 返回
public House buildHouse() {
return house;
}

CommonHouse

public class CommonHouse extends HouseBuilder {

@Override
public void buildBasic() {
// TODO Auto-generated method stub
System.out.println(" 普通房子打地基5米 ");
}

@Override
public void buildWalls() {
// TODO Auto-generated method stub
System.out.println(" 普通房子砌墙10cm ");
}

@Override
public void roofed() {
// TODO Auto-generated method stub
System.out.println(" 普通房子屋顶 ");
}

}

HighBuilding

public class HighBuilding extends HouseBuilder {

@Override
public void buildBasic() {
// TODO Auto-generated method stub
System.out.println(" 高楼的打地基100米 ");
}

@Override
public void buildWalls() {
// TODO Auto-generated method stub
System.out.println(" 高楼的砌墙20cm ");
}

@Override
public void roofed() {
// TODO Auto-generated method stub
System.out.println(" 高楼的透明屋顶 ");
}

}

HouseDirector

//指挥者，这里去指定制作流程，返回产品
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.roofed();
return houseBuilder.buildHouse();
}
}

测试

public class Client {
public static void main(String[] args) {

//盖普通房子
CommonHouse commonHouse = new CommonHouse();
//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("输出流程");

System.out.println("--------------------------");
//盖高楼
HighBuilding highBuilding = new HighBuilding();
//重置建造者
houseDirector.setHouseBuilder(highBuilding);
//完成盖房子，返回产品(高楼)
houseDirector.constructHouse();
}
}

类似建造者模式的jdk源码

建 造者模式在 JDK 的应用和源码分 析

总结

源码地址

​​https://github.com/hufanglei/java-design/tree/builder​​

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