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北京百度推广电话,seo优化视频教程,找竞价托管公司,wdlinux wordpress工厂方法模式是一种创建型设计模式#xff0c;它定义了一个创建对象的接口#xff0c;但让子类决定实例化哪个类。这种模式将对象的实例化推迟到子类#xff0c;从而实现了创建逻辑与使用逻辑的分离。 核心概念解析 image 工厂方法模式包含以下几个关键角色#xff1a; 产…工厂方法模式是一种创建型设计模式它定义了一个创建对象的接口但让子类决定实例化哪个类。这种模式将对象的实例化推迟到子类从而实现了创建逻辑与使用逻辑的分离。核心概念解析image工厂方法模式包含以下几个关键角色产品接口Product Interface定义了产品对象的通用接口具体产品Concrete Products实现产品接口的具体类创建者Creator声明工厂方法返回产品对象具体创建者Concrete Creators重写工厂方法返回具体产品实例为什么使用工厂方法模式解决紧耦合问题考虑以下紧耦合的代码class Car {drive() {console.log(Driving a car);}}class Truck {drive() {console.log(Driving a truck);}}// 客户端代码直接依赖具体类const vehicle1 new Car();const vehicle1 new Truck();这种写法的问题在于客户端代码直接依赖于具体类一旦需要添加新的车辆类型或修改创建逻辑就需要在所有使用的地方进行修改。实现开闭原则工厂方法模式帮助你的代码遵循开闭原则对扩展开放对修改关闭。你可以添加新的产品类型而无需修改现有代码。工厂方法模式实现让我们通过一个完整的示例来理解工厂方法模式。第一步定义产品接口interface Vehicle {drive(): void;getInfo(): string;}第二步实现具体产品类class Car implements Vehicle {drive() {console.log(Driving a car);}getInfo(): string {return This is a car with 4 seats;}}class Truck implements Vehicle {drive() {console.log(Driving a truck);}getInfo(): string {return This is a truck for heavy loads;}}class Motorcycle implements Vehicle {drive() {console.log(Riding a motorcycle);}getInfo(): string {return This is a motorcycle with 2 wheels;}}第三步创建抽象创建者类abstract class VehicleFactory {// 工厂方法public abstract createVehicle(): Vehicle;// 业务逻辑方法public deliverVehicle(): string {const vehicle this.createVehicle();vehicle.drive();return vehicle.getInfo();}}第四步实现具体创建者类class CarFactory extends VehicleFactory {public createVehicle(): Vehicle {return new Car();}}class TruckFactory extends VehicleFactory {public createVehicle(): Vehicle {return new Truck();}}class MotorcycleFactory extends VehicleFactory {public createVehicle(): Vehicle {return new Motorcycle();}}第五步客户端使用function clientCode(factory: VehicleFactory) {console.log(Client: Delivery process started...);const result factory.deliverVehicle();console.log(result);}// 使用不同的工厂创建不同的产品console.log(App: Launched with CarFactory.);clientCode(new CarFactory());console.log(\nApp: Launched with TruckFactory.);clientCode(new TruckFactory());console.log(\nApp: Launched with MotorcycleFactory.);clientCode(new MotorcycleFactory());高级应用参数化工厂方法在某些场景下你可能希望通过参数来决定创建哪种产品class UniversalVehicleFactory extends VehicleFactory {constructor(private vehicleType: car | truck | motorcycle) {super();}public createVehicle(): Vehicle {switch (this.vehicleType) {case car:return new Car();case truck:return new Truck();case motorcycle:return new Motorcycle();default:throw new Error(Unknown vehicle type);}}}// 使用参数化工厂const carFactory new UniversalVehicleFactory(car);clientCode(carFactory);结合 TypeScript 的高级特性使用泛型增强类型安全abstract class GenericVehicleFactoryT extends Vehicle {public abstract createVehicle(): T;public deliverVehicle(): string {const vehicle this.createVehicle();vehicle.drive();return vehicle.getInfo();}}class GenericCarFactory extends GenericVehicleFactoryCar {public createVehicle(): Car {return new Car();}}利用枚举提高代码可读性enum VehicleType {CAR car,TRUCK truck,MOTORCYCLE motorcycle}class EnumVehicleFactory extends VehicleFactory {constructor(private type: VehicleType) {super();}public createVehicle(): Vehicle {switch (this.type) {case VehicleType.CAR:return new Car();case VehicleType.TRUCK:return new Truck();case VehicleType.MOTORCYCLE:return new Motorcycle();}}}实际应用场景场景一UI 组件库在不同平台Web、Mobile、Desktop上创建相同功能的 UI 组件interface Button {render(): void;onClick(callback: () void): void;}class WebButton implements Button {render() { console.log(Rendering web button); }onClick(callback: () void) { /* web 实现 */ }}class MobileButton implements Button {render() { console.log(Rendering mobile button); }onClick(callback: () void) { /* mobile 实现 */ }}abstract class UIFactory {abstract createButton(): Button;abstract createModal(): Modal; // 假设有 Modal 接口}class WebUIFactory extends UIFactory {createButton(): Button { return new WebButton(); }createModal(): Modal { return new WebModal(); }}场景二数据库连接工厂interface DatabaseConnection {connect(): void;query(sql: string): any[];}class MySQLConnection implements DatabaseConnection {connect() { console.log(Connecting to MySQL); }query(sql: string) { return []; }}class PostgreSQLConnection implements DatabaseConnection {connect() { console.log(Connecting to PostgreSQL); }query(sql: string) { return []; }}abstract class DatabaseFactory {abstract createConnection(): DatabaseConnection;}class MySQLFactory extends DatabaseFactory {createConnection(): DatabaseConnection {return new MySQLConnection();}}真实案例TypeORM 的 Driver 工厂 使用工厂方法来根据数据库类型创建不同驱动实例。export class DriverFactory {create(connection: Connection): Driver {switch (connection.options.type) {case mysql:return new MysqlDriver(connection)case postgres:return new PostgresDriver(connection)case sqlite:return new SqliteDriver(connection)// ...}}}基于数据库类型返回不同的 Driver 子类统一入口 create()使用者不关心具体 driver只依赖 Driver 接口工厂方法模式的优势与局限优势避免紧耦合客户端代码只依赖于抽象接口不依赖于具体类单一职责原则将创建逻辑集中在一个地方便于维护开闭原则添加新产品类型时无需修改现有代码代码可测试性可以轻松创建模拟对象进行单元测试局限代码复杂度增加需要引入多个额外的类和接口可能过度设计对于简单场景直接实例化可能更合适实践建议适时使用当预计会有多种类似产品或创建逻辑比较复杂时使用结合依赖注入在大型应用中结合依赖注入容器使用效果更佳文档化工厂意图明确每个工厂的职责和适用场景考虑简单工厂如果产品类型不多可以考虑使用简单工厂模式