Java设计模式--建造者模式

àì夳堔傛蜴生んèń 2022-11-19 01:18 120阅读 0赞

原文网址：[Java设计模式--建造者模式\_IT利刃出鞘的博客-CSDN博客][Java_--_IT_-CSDN]

# 其他网址 #

[【狂神说Java】通俗易懂的23种设计模式教学（停更）\_哔哩哔哩 (゜-゜)つロ 干杯~-bilibili][Java_23_ _-_ _-bilibili]

# 有序的建造者模式 #

## 简介 ##

**场景**

> 假设的场景：建一座房子。需要如下步骤：打地基、建墙体、铺电线、粉刷。这些步骤的顺序是不可颠倒的，而且任意一步不可缺少。

**所有的类**

> ![20210414230137405.png][]

## 代码 ##

### 房屋产品 ###

>     package org.example.builder.product;
>     
>     public class House {
>         private String base;
>         private String wall;
>         private String wire;
>         private String paint;
>     
>         public String getBase() {
>             return base;
>         }
>     
>         public void setBase(String base) {
>             this.base = base;
>         }
>     
>         public String getWall() {
>             return wall;
>         }
>     
>         public void setWall(String wall) {
>             this.wall = wall;
>         }
>     
>         public String getWire() {
>             return wire;
>         }
>     
>         public void setWire(String wire) {
>             this.wire = wire;
>         }
>     
>         public String getPaint() {
>             return paint;
>         }
>     
>         public void setPaint(String paint) {
>             this.paint = paint;
>         }
>     
>         @Override
>         public String toString() {
>             return "House{" +
>                     "base='" + base + '\'' +
>                     ", wall='" + wall + '\'' +
>                     ", wire='" + wire + '\'' +
>                     ", paint='" + paint + '\'' +
>                     '}';
>         }
>     }

### 建造者 ###

**抽象类**

>     package org.example.builder.product;
>     
>     public abstract class Builder {
>         public abstract Builder buildBase(String base);
>     
>         public abstract Builder buildWall(String wall);
>     
>         public abstract Builder buildWire(String wire);
>     
>         public abstract Builder buildPaint(String paint);
>     
>         public abstract House build();
>     }

**实现类**

> 重点：在构造函数中，创建一个产品。
> 
>     package org.example.builder.product;
>     
>     public class Woker extends Builder {
>         private House house;
>     
>         public Woker() {
>             this.house = new House();
>         }
>     
>         @Override
>         public Builder buildBase(String base) {
>             System.out.println("建造地基");
>             house.setBase(base);
>             return this;
>         }
>     
>         @Override
>         public Builder buildWall(String wall) {
>             System.out.println("建造墙壁");
>             house.setWall(wall);
>             return this;
>         }
>     
>         @Override
>         public Builder buildWire(String wire) {
>             System.out.println("铺设电线");
>             house.setWire(wire);
>             return this;
>         }
>     
>         @Override
>         public Builder buildPaint(String paint) {
>             System.out.println("粉刷");
>             house.setPaint(paint);
>             return this;
>         }
>     
>         @Override
>         public House build() {
>             return this.house;
>         }
>     }

### 指挥者 ###

**简介**

> 指挥者决定建造房子的顺序
> 
> 指挥者决定具体每一步做什么样的建造。这样，可以造出简约、有大电流的电线、有隔音墙、地基为平房地基的平房，也可以造出其他配置的房子，比如：豪华粉刷、大电流、隔音墙、地基为高楼地基的高楼等。

**代码**

>     package org.example.builder;
>     
>     import org.example.builder.product.Builder;
>     import org.example.builder.product.House;
>     
>     public class Director {
>         public static House build(Builder builder) {
>             return builder
>                     .buildBase("平房地基")
>                     .buildWall("隔音墙")
>                     .buildWire("大电流的电线")
>                     .buildPaint("简约粉刷")
>                     .build();
>         }
>     }

### 测试类 ###

**简介**

> 指挥者（包工头）去指挥具体的工人去按照自己的步骤建造房子。

**代码**

>     package org.example.builder;
>     
>     import org.example.builder.product.House;
>     import org.example.builder.product.Woker;
>     
>     public class Consumer {
>         public static void main(String[] args) {
>             House build = Director.build(new Woker());
>             System.out.println(build);
>         }
>     }

**执行结果**

>     建造地基
>     建造墙壁
>     铺设电线
>     粉刷
>     House{base='平房地基', wall='隔音墙', wire='大电流的电线', paint='简约粉刷'}

# 无序的建造者模式 #

## **简介** ##

**场景**

> 假设的场景：你去买一款手机，这款手机有多种可选的配置：颜色、运行内存、机身存储。
> 
>  *  如你果不指定，则给一个默认项，比如：黑色，6G，128G。
>  *  如果你指定某些项，则给你你指定的配置，其他没指定的依然采用默认的配置。

**所有的类**

> ![20210414192748159.png][]

**对比有序的建造者模式**

> 无序，且每个字段有默认项，由用户来直接设置。

## **代码** ##

### **手机产品** ###

> 重点：提供静态的创建builder的方法；字段要设置默认值。
> 
>     package org.example.builder.product;
>     
>     public class Phone {
>         private String color = "黑色（默认）";
>         private String runningStorage = "6G（默认）";
>         private String phoneStorage = "128G（默认）";
>     
>         public static DefaultBuilder builder() {
>             return new DefaultBuilder();
>         }
>     
>         public String getColor() {
>             return color;
>         }
>     
>         public void setColor(String color) {
>             this.color = color;
>         }
>     
>         public String getRunningStorage() {
>             return runningStorage;
>         }
>     
>         public void setRunningStorage(String runningStorage) {
>             this.runningStorage = runningStorage;
>         }
>     
>         public String getPhoneStorage() {
>             return phoneStorage;
>         }
>     
>         public void setPhoneStorage(String phoneStorage) {
>             this.phoneStorage = phoneStorage;
>         }
>     
>         @Override
>         public String toString() {
>             return "Phone{" +
>                     "color='" + color + '\'' +
>                     ", runningStorage='" + runningStorage + '\'' +
>                     ", phoneStorage='" + phoneStorage + '\'' +
>                     '}';
>         }
>     }

### **建造者** ###

**建造者抽象类**

>     package org.example.builder.product;
>     
>     public abstract class Builder {
>         public abstract Builder buildColor(String color);
>     
>         public abstract Builder buildRunningStorage(String runningStorage);
>     
>         public abstract Builder buildPhoneStorage(String phoneStorage);
>     
>         public abstract Phone build();
>     }

**建造者实现类**

> 重点：构造函数里边，要去构造一个产品。
> 
>     package org.example.builder.product;
>     
>     public class DefaultBuilder extends Builder {
>         private Phone phone;
>     
>         public DefaultBuilder() {
>             this.phone = new Phone();
>         }
>     
>         @Override
>         public Builder buildColor(String color) {
>             phone.setColor(color);
>             return this;
>         }
>     
>         @Override
>         public Builder buildRunningStorage(String runningStorage) {
>             phone.setRunningStorage(runningStorage);
>             return this;
>         }
>     
>         @Override
>         public Builder buildPhoneStorage(String phoneStorage) {
>             phone.setPhoneStorage(phoneStorage);
>             return this;
>         }
>     
>         @Override
>         public Phone build() {
>             return phone;
>         }
>     }

### **测试类** ###

>     package org.example.builder;
>     
>     import org.example.builder.product.Phone;
>     
>     public class Consumer {
>         public static void main(String[] args) {
>             Phone phone = Phone.builder()
>                     .buildColor("红色")
>                     .buildRunningStorage("8G")
>                     .build();
>             System.out.println(phone);
>         }
>     }

> **执行结果**
> 
>     Phone{color='红色', runningStorage='8G', phoneStorage='128G（默认）'}

[Java_--_IT_-CSDN]: https://knife.blog.csdn.net/article/details/115682200
[Java_23_ _-_ _-bilibili]: https://www.bilibili.com/video/BV1mc411h719?p=5
[20210414230137405.png]: /images/20221022/c2a8856e08d54353942b1437c6f96763.png
[20210414192748159.png]: /images/20221022/14945dbe96e441f9ac64e5db8573daae.png