23种设计模式 - 博客

此笔记从B站狂神说Java 获取

<>什么是设计模式

<>学习设计模式的意义

<>GoF23

<>oop七大原则

（1）开闭原则: 一个软件的实体应当对扩展开放，对修改关闭；

（2）里氏替换原则:继承必须确保超类所拥有的性质在子类中仍然成立

（3）依赖倒置原则:要面向接口编程，不要面向实现编程。

（4）单一职责原则:控制类的粒度大小、将对象解耦、提高其内聚性。

（5）接口隔离原则:要为各个类建立它们需要的专用接口

（6）迪米特法则:只与你的直接朋友交谈，不跟“陌生人”说话。

（7）合成复用原则:尽量先使用组合或者聚合等关联关系来实现，其次才考虑使用继承关系来实现。

<>工厂模式

1、作用：实现创建者和调用者分离

2、00P七大原则：

（1）开闭原则: 一个软件的实体应当对扩展开放，对修改关闭；

（2）依赖倒转原则:要针对接口编程，不要针对实现编程；

（3）迪米特法则:只与你直接的朋友通信，而避免和陌生人通信；

3、核心本质:

（1）实例化对象不使用new, 用工厂方法代替

（2）将选择实现类, 创建对象统一管理和控制。从而将调用者跟我们的实现类解耦。

简单工厂模式

1.Car接口
package com.etc.factory.simple; public interface Car { void name(); }
2.车 WuLing
package com.etc.factory.simple; public class WuLing implements Car{ @Override
public void name() { System.out.println("五菱"); } }
3.车 Tesla
package com.etc.factory.simple; public class Tesla implements Car{ @Override
public void name() { System.out.println("特斯拉"); } }
4.CarFactory (创建工厂)
package com.etc.factory.simple; //简单工厂模式静态工厂模式 //开闭原则 public class CarFactory
{ //方法一 public static Car getCar(String car) { //如果添加其他类，需要修改下列代码，修改逻辑 if (car.
equals("五菱")) { return new WuLing(); }else if (car.equals("特斯拉")) { return new
Tesla(); }else { return null; } } //出现问题增加一个车呢？ //方法二不修改原逻辑的情况下 public static
Car getwuling() { return new WuLing(); } public static Car getTesla() { return
new Tesla(); } }
5.Consumer
package com.etc.factory.simple; public class Consumer { public static void main
(String[] args) { // 1 常规创建 // Car car1=new WuLing(); // Car car2=new Tesla();
// 2 使用工厂创建 Car car1 = CarFactory.getCar("五菱"); Car car2 = CarFactory.getCar(
"特斯拉"); car1.name(); car2.name(); } }
工厂方法模式

1.car接口
package com.etc.factory.method; public interface Car { void name(); }
2.CarFactory接口
package com.etc.factory.method; //工厂方法模式 public interface CarFactory { Car
getCar(); }
3.车 WuLing
package com.etc.factory.simple; public class WuLing implements Car{ @Override
public void name() { System.out.println("五菱"); } }
4.给五菱单独创建个工厂 WuLingFactory
package com.etc.factory.method; public class WuLingFactory implements
CarFactory { @Override public Car getCar() { return new WuLing(); } }
5.车 Tesla
package com.etc.factory.simple; public class Tesla implements Car{ @Override
public void name() { System.out.println("特斯拉"); } }
6.给Tesla单独创建个工厂 TeslaFactory
package com.etc.factory.method; public class TeslaFactory implements CarFactory
{ @Override public Car getCar() { return new Tesla(); } }
7.Consumer
package com.etc.factory.method; public class Consumer { public static void main
(String[] args) { Car car1 = new WuLingFactory().getCar(); Car car2 = new
TeslaFactory().getCar(); car1.name(); car2.name(); } }
结构复杂度: simple

代码复杂度: simple

编程复杂度: simple

管理上的复杂度: simple

根据设计原则:工厂方法模式！

根据实际业务:简单工厂模式！

图片解释

<>抽象工厂模式

代码演示

1.IPhoneProduct接口
//手机产品接口 public interface IPhoneProduct { void start(); void shutdown(); void
callup(); void sendMS(); }
2.IRouteProduct接口
//路由器产品接口 public interface IRouteProduct { void start(); void shutdown(); void
openWife(); void setting(); }
3.小米手机
package com.etc.factory.abstract1; public class XiaomiPhone implements
IPhoneProduct { @Override public void start() { System.out.println("开启小米手机"); }
@Override public void shutdown() { System.out.println("关闭小米手机"); } @Override
public void callup() { System.out.println("小米打电话"); } @Override public void
sendMS() { System.out.println("小米发短信"); } }
4.小米路由器
package com.etc.factory.abstract1; public class XiaomiRouter implements
IRouteProduct{ @Override public void start() { System.out.println("启动小米路由器"); }
@Override public void shutdown() { System.out.println("关闭小米路由器"); } @Override
public void openWife() { System.out.println("开启小米wifi"); } @Override public void
setting() { System.out.println("设置小米路由器"); } }
5.华为手机
package com.etc.factory.abstract1; public class HuaweiPhone implements
IPhoneProduct { @Override public void start() { System.out.println("开启华为手机"); }
@Override public void shutdown() { System.out.println("关闭华为手机"); } @Override
public void callup() { System.out.println("华为打电话"); } @Override public void
sendMS() { System.out.println("华为发短信"); } }
6.华为路由器
package com.etc.factory.abstract1; public class HuaweiRouter implements
IRouteProduct{ @Override public void start() { System.out.println("启动华为路由器"); }
@Override public void shutdown() { System.out.println("关闭华为路由器"); } @Override
public void openWife() { System.out.println("开启华为wifi"); } @Override public void
setting() { System.out.println("设置华为路由器"); } }
7.抽象工厂
package com.etc.factory.abstract1; //抽象产品工厂 public interface IProductFactory {
//生产手机 IPhoneProduct iphoneProduct(); //生产路由器 IRouteProduct routeProduct(); }
8.小米工厂
package com.etc.factory.abstract1; public class XiaomiFactory implements
IProductFactory{ @Override public IPhoneProduct iphoneProduct() { return new
XiaomiPhone(); } @Override public IRouteProduct routeProduct() { return new
XiaomiRouter(); } }
9.华为工厂
package com.etc.factory.abstract1; public class HuaweiFactory implements
IProductFactory{ @Override public IPhoneProduct iphoneProduct() { return new
HuaweiPhone(); } @Override public IRouteProduct routeProduct() { return new
HuaweiRouter(); } }
10.客户端使用
package com.etc.factory.abstract1; public class Client { public static void
main(String[] args) { System.out.println("=======小米系列产品=========");
XiaomiFactory xiaomiFactory = new XiaomiFactory(); IPhoneProduct iPhoneProduct =
xiaomiFactory.iphoneProduct(); iPhoneProduct.callup(); iPhoneProduct.sendMS();
IRouteProduct iRouteProduct = xiaomiFactory.routeProduct(); iRouteProduct.
openWife(); System.out.println("=======华为系列产品========="); HuaweiFactory
huaweiFactory= new HuaweiFactory(); iPhoneProduct = huaweiFactory.iphoneProduct(
); iPhoneProduct.callup(); iPhoneProduct.sendMS(); iRouteProduct = huaweiFactory
.routeProduct(); iRouteProduct.openWife(); } }
<>建造者模式

代码演示

1.抽象的建造者
package com.etc.factory.builder; //抽象的建造者：方法 public abstract class Builder {
abstract void buildA();//地基 abstract void buildB();//钢筋工程 abstract void buildC()
;//铺电线 abstract void buildD();//粉刷 //完工：得到产品 abstract Product getProduct(); }
2.产品：房子
package com.etc.factory.builder; //产品：房子 public class Product { private String
buildA; private String buildB; private String buildC; private String buildD;
public String getBuildA() { return buildA; } public void setBuildA(String buildA
) { this.buildA = buildA; } public String getBuildB() { return buildB; } public
void setBuildB(String buildB) { this.buildB = buildB; } public String getBuildC(
) { return buildC; } public void setBuildC(String buildC) { this.buildC = buildC
; } public String getBuildD() { return buildD; } public void setBuildD(String
buildD) { this.buildD = buildD; } @Override public String toString() { return
"Product{" + "buildA='" + buildA + '\'' + ", buildB='" + buildB + '\'' + ",
buildC='" + buildC + '\'' + ", buildD='" + buildD + '\'' + '}'; } }
3.具体的建造者
package com.etc.factory.builder; //具体的建造者：工人 public class Worker extends
Builder { private Product product; public Worker(){ product=new Product(); }
@Override void buildA() { product.setBuildA("地基"); System.out.println("地基"); }
@Override void buildB() { product.setBuildB("钢筋工程"); System.out.println("钢筋工程");
} @Override void buildC() { product.setBuildB("铺电线"); System.out.println("铺电线");
} @Override void buildD() { product.setBuildB("粉刷"); System.out.println("粉刷"); }
@Override Product getProduct() { return product; } }
4.指挥者
package com.etc.factory.builder; //指挥：核心负责指挥构建一个工程，工程如何构建，由它决定 public class
Director { //指挥工人按照顺序建房子 public Product build(Builder builder){ builder.buildA()
; builder.buildB(); builder.buildC(); builder.buildD(); return builder.
getProduct(); } }
5.测试
package com.etc.factory.builder; public class Test { public static void main(
String[] args) { //指挥 Director director = new Director(); //指挥具体的工人完成产品
Product build = director.build(new Worker()); //顺序由工人决定 System.out.println(build
.toString()); } }
代码再理解

1.建造者
package com.etc.factory.builder2; //建造者 public abstract class Builder {
abstract Builder buildA(String msg);//汉堡 abstract Builder buildB(String msg);
//可乐 abstract Builder buildC(String msg);//薯条 abstract Builder buildD(String msg
);//甜点 abstract Product getProduct(); }
2.产品
package com.etc.factory.builder2; //产品：套餐 public class Product { private
String BuildA="汉堡"; private String BuildB="可乐"; private String BuildC="薯条";
private String BuildD="甜点"; public String getBuildA() { return BuildA; } public
void setBuildA(String buildA) { BuildA = buildA; } public String getBuildB() {
return BuildB; } public void setBuildB(String buildB) { BuildB = buildB; }
public String getBuildC() { return BuildC; } public void setBuildC(String buildC
) { BuildC = buildC; } public String getBuildD() { return BuildD; } public void
setBuildD(String buildD) { BuildD = buildD; } @Override public String toString()
{ return "Product{" + "BuildA='" + BuildA + '\'' + ", BuildB='" + BuildB + '\''
+ ", BuildC='" + BuildC + '\'' + ", BuildD='" + BuildD + '\'' + '}'; } }
3.具体的建造者
package com.etc.factory.builder2; //具体的建造者 public class Worker extends Builder{
private Product product; public Worker(){ product=new Product(); } @Override
Builder buildA(String msg) { product.setBuildA(msg); return this; } @Override
Builder buildB(String msg) { product.setBuildB(msg); return this; } @Override
Builder buildC(String msg) { product.setBuildC(msg); return this; } @Override
Builder buildD(String msg) { product.setBuildD(msg); return this; } @Override
Product getProduct() { return product; } }
4.测试
package com.etc.factory.builder2; public class Test { public static void main(
String[] args) { //服务员 Worker worker = new Worker(); //链式编程 :
在原来的基础上，可以自由组合了，如果不组合，也有默认的套餐 Product product = worker.buildA("全家桶") .buildB(
"雪碧").getProduct(); System.out.println(product.toString());
//Product{BuildA='全家桶', BuildB='雪碧', BuildC='薯条', BuildD='甜点'} } }
<>原型模式

代码演示 demo01

1.Video
package com.etc.prototype.demo01; import java.util.Date; /** * 1.实现一个接口
Cloneable * 2.重写一个方法 clone() */ public class Video implements Cloneable{ private
String name; private Date createTime; @Override protected Object clone() throws
CloneNotSupportedException { return super.clone(); } public Video() { } public
Video(String name, Date createTime) { this.name = name; this.createTime =
createTime; } public String getName() { return name; } public void setName(
String name) { this.name = name; } public Date getCreateTime() { return
createTime; } public void setCreateTime(Date createTime) { this.createTime =
createTime; } @Override public String toString() { return "Video{" + "name='" +
name+ '\'' + ", createTime=" + createTime + '}'; } }
2.Bilibili
package com.etc.prototype.demo01; import java.util.Date; /** * 客户端：克隆 */
public class Bilibili { public static void main(String[] args) throws
CloneNotSupportedException { //原型对象 v1 Date date = new Date(); Video v1 = new
Video("狂神说java", date); Video v2 = (Video) v1.clone(); System.out.println("v1=>"
+v1); System.out.println("v2=>"+v2); System.out.println("======="); date.setTime
(21312231); //没有发生改变 System.out.println("v1=>"+v1); System.out.println("v2=>"+v2
); /* v1=>Video{name='狂神说java', createTime=Sat Feb 19 14:39:15 CST 2022}
v2=>Video{name='狂神说java', createTime=Sat Feb 19 14:39:15 CST 2022} =======
v1=>Video{name='狂神说java', createTime=Thu Jan 01 13:55:12 CST 1970}
v2=>Video{name='狂神说java', createTime=Thu Jan 01 13:55:12 CST 1970} */ } } /*
//v1 克隆 v2 // Video v2 = new Video("狂神说java", date); Video v2 = (Video)
v1.clone(); System.out.println("v2=>"+v2);
System.out.println("v2=>hash:"+v2.hashCode()); * v1=>Video{name='狂神说java',
createTime=Sat Feb 19 14:33:53 CST 2022} v1=>hash:1028214719
v2=>Video{name='狂神说java', createTime=Sat Feb 19 14:33:53 CST 2022}
v2=>hash:500977346 v2.setName("Clone:狂神说java"); System.out.println("v2=>"+v2);
//v2=>Video{name='Clone:狂神说java', createTime=Sat Feb 19 14:34:49 CST 2022} */

代码演示 demo02 深克隆

1.Video
package com.etc.prototype.demo02; import java.util.Date; public class Video
implements Cloneable{ private String name; private Date createTime; @Override
protected Object clone() throws CloneNotSupportedException { Object obj = super.
clone(); //实现深克隆~ Video v = (Video) obj; v.createTime = (Date) this.createTime.
clone();//将这个对象的属性也进行克隆~ return obj; } public Video() { } public Video(String
name, Date createTime) { this.name = name; this.createTime = createTime; }
public String getName() { return name; } public void setName(String name) { this
.name = name; } public Date getCreateTime() { return createTime; } public void
setCreateTime(Date createTime) { this.createTime = createTime; } @Override
public String toString() { return "Video{" + "name='" + name + '\'' + ",
createTime=" + createTime + '}'; } }
2.Bilibili
package com.etc.prototype.demo02; import java.util.Date; //原型模式+工厂模式 ==》new
《=》原型模式 public class Bilibili { public static void main(String[] args) throws
CloneNotSupportedException { //原型对象 v1 Date date = new Date(); Video v1 = new
Video("狂神说java", date); Video v2 = (Video) v1.clone(); System.out.println("v1=>"
+v1); System.out.println("v2=>"+v2); System.out.println("======="); date.setTime
(21312231); System.out.println("v1=>"+v1); System.out.println("v2=>"+v2); /*
v1=>Video{name='狂神说java', createTime=Sat Feb 19 14:43:22 CST 2022}
v2=>Video{name='狂神说java', createTime=Sat Feb 19 14:43:22 CST 2022} =======
v1=>Video{name='狂神说java', createTime=Thu Jan 01 13:55:12 CST 1970}
v2=>Video{name='狂神说java', createTime=Sat Feb 19 14:43:22 CST 2022} */ } }
<>适配器模式

代码演示

1.Adaptee
package com.etc.adapter; //要被适配的类：网线 public class Adaptee { public void
request(){ System.out.println("连接网线上网"); } }
2.NetToUsb
package com.etc.adapter; //接口转换器的抽象实现 public interface NetToUsb { //作用：处理请求
网线=》usb public void handleRequest(); }
3.Adapter
package com.etc.adapter; //真正的适配器需要连接USB，连接网线 //继承 (类适配器单继承) //组合 (对象适配器：常用)
public class Adapter extends Adaptee implements NetToUsb{ @Override public void
handleRequest() { super.request();//可以上网了 } }
4.Computer
package com.etc.adapter; //客户端类：想上网插不上网线 public class Computer {
//我们的电脑需要连接上转接器才可以上网 public void net(NetToUsb netToUsb){ //上网的具体实现~ 找一个转接头
netToUsb.handleRequest(); } public static void main(String[] args) { //电脑适配器网线
Computer computer = new Computer(); Adaptee adaptee = new Adaptee(); Adapter
adapter= new Adapter(); Adapter2 adapter2=new Adapter2(adaptee); //
computer.net(adapter); computer.net(adapter2); } }
升级版 Adapter2
package com.etc.adapter; //真正的适配器需要连接USB，连接网线 //继承 (类适配器单继承) //组合 (对象适配器：常用)
public class Adapter2 implements NetToUsb{ private Adaptee adaptee; public
Adapter2(Adaptee adaptee) { this.adaptee = adaptee; } @Override public void
handleRequest() { adaptee.request(); } }
<>桥接模式

代码演示

1.Brand
package com.etc.bridge; //品牌 public interface Brand { void info(); }
2.Lenovo联想品牌
package com.etc.bridge; //联想品牌 public class Lenovo implements Brand{ @Override
public void info() { System.out.print("联想"); } }
3.苹果品牌
package com.etc.bridge; //苹果品牌 public class Apple implements Brand{ @Override
public void info() { System.out.print("苹果"); } }
4.组合
package com.etc.bridge; //抽象的电脑类型类 public abstract class Computer { //组合品牌
protected Brand brand; public Computer(Brand brand) { this.brand = brand; }
public void info(){ brand.info();//自带品牌 } } class Desktop extends Computer{
public Desktop(Brand brand) { super(brand); } @Override public void info() {
super.info(); System.out.print("台式机"); } } class Laptop extends Computer{ public
Laptop(Brand brand) { super(brand); } @Override public void info() { super.info(
); System.out.print("笔记本"); } }
5.测试
package com.etc.bridge; public class Test { public static void main(String[]
args) { //苹果笔记本 Computer computer = new Laptop(new Apple()); computer.info();
System.out.println(); //联想台式机 Computer computer2 = new Desktop(new Lenovo());
computer2.info(); } }

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