深入理解Java工厂模式的三种实现方式

// 抽象产品类
interface Product {
    void print();
}

// 具体产品类A
class ProductA implements Product {
    @Override
    public void print() {
        System.out.println("Product A");
    }
}

// 具体产品类B
class ProductB implements Product {
    @Override
    public void print() {
        System.out.println("Product B");
    }
}

// 工厂类
class SimpleFactory {
    public static Product createProduct(String type) {
        if (type.equals("A")) {
            return new ProductA();
        } else if (type.equals("B")) {
            return new ProductB();
        } else {
            throw new IllegalArgumentException("Invalid product type.");
        }
    }
}

// 测试代码
public class Main {
    public static void main(String[] args) {
        Product productA = SimpleFactory.createProduct("A");
        productA.print();  // 输出：Product A
        
        Product productB = SimpleFactory.createProduct("B");
        productB.print();  // 输出：Product B
    }
}

// 抽象产品类
interface Product {
    void print();
}

// 具体产品类A
class ProductA implements Product {
    @Override
    public void print() {
        System.out.println("Product A");
    }
}

// 具体产品类B
class ProductB implements Product {
    @Override
    public void print() {
        System.out.println("Product B");
    }
}

// 抽象工厂类
interface Factory {
    Product createProduct();
}

// 具体工厂类A
class FactoryA implements Factory {
    @Override
    public Product createProduct() {
        return new ProductA();
    }
}

// 具体工厂类B
class FactoryB implements Factory {
    @Override
    public Product createProduct() {
        return new ProductB();
    }
}

// 测试代码
public class Main {
    public static void main(String[] args) {
        Factory factoryA = new FactoryA();
        Product productA = factoryA.createProduct();
        productA.print();  // 输出：Product A
        
        Factory factoryB = new FactoryB();
        Product productB = factoryB.createProduct();
        productB.print();  // 输出：Product B
    }
}

// 抽象产品类A
interface ProductA {
    void print();
}

// 具体产品A1
class ProductA1 implements ProductA {
    @Override
    public void print() {
        System.out.println("Product A1");
    }
}

// 具体产品A2
class ProductA2 implements ProductA {
    @Override
    public void print() {
        System.out.println("Product A2");
    }
}

// 抽象产品类B
interface ProductB {
    void print();
}

// 具体产品B1
class ProductB1 implements ProductB {
    @Override
    public void print() {
        System.out.println("Product B1");
    }
}

// 具体产品B2
class ProductB2 implements ProductB {
    @Override
    public void print() {
        System.out.println("Product B2");
    }
}

// 抽象工厂类
interface AbstractFactory {
    ProductA createProductA();
    ProductB createProductB();
}

// 具体工厂类1
class ConcreteFactory1 implements AbstractFactory {
    @Override
    public ProductA createProductA() {
        return new ProductA1();
    }
    
    @Override
    public ProductB createProductB() {
        return new ProductB1();
    }
}

// 具体工厂类2
class ConcreteFactory2 implements AbstractFactory {
    @Override
    public ProductA createProductA() {
        return new ProductA2();
    }
    
    @Override
    public ProductB createProductB() {
        return new ProductB2();
    }
}

// 测试代码
public class Main {
    public static void main(String[] args) {
        AbstractFactory factory1 = new ConcreteFactory1();
        ProductA productA1 = factory1.createProductA();
        productA1.print();  // 输出：Product A1
        
        ProductB productB1 = factory1.createProductB();
        productB1.print();  // 输出：Product B1
        
        AbstractFactory factory2 = new ConcreteFactory2();
        ProductA productA2 = factory2.createProductA();
        productA2.print();  // 输出：Product A2
        
        ProductB productB2 = factory2.createProductB();
        productB2.print();  // 输出：Product B2
    }
}