深度剖析Java工厂模式的三种不同形式

// 抽象产品类
public abstract class Product {
    public abstract void use();
}

// 具体产品类A
public class ProductA extends Product {
    @Override
    public void use() {
        System.out.println("Product A is used.");
    }
}

// 具体产品类B
public class ProductB extends Product {
    @Override
    public void use() {
        System.out.println("Product B is used.");
    }
}

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

// 测试代码
public class Client {
    public static void main(String[] args) {
        Product productA = SimpleFactory.createProduct("A");
        productA.use(); // Output: Product A is used.

        Product productB = SimpleFactory.createProduct("B");
        productB.use(); // Output: Product B is used.
    }
}

// 抽象产品类
public abstract class Product {
    public abstract void use();
}

// 具体产品类A
public class ProductA extends Product {
    @Override
    public void use() {
        System.out.println("Product A is used.");
    }
}

// 具体产品类B
public class ProductB extends Product {
    @Override
    public void use() {
        System.out.println("Product B is used.");
    }
}

// 抽象工厂类
public abstract class Factory {
    public abstract Product createProduct();
}

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

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

// 测试代码
public class Client {
    public static void main(String[] args) {
        Factory factoryA = new FactoryA();
        Product productA = factoryA.createProduct();
        productA.use(); // Output: Product A is used.

        Factory factoryB = new FactoryB();
        Product productB = factoryB.createProduct();
        productB.use(); // Output: Product B is used.
    }
}

// 抽象产品类A
public abstract class ProductA {
    public abstract void use();
}

// 具体产品类A1
public class ProductA1 extends ProductA {
    @Override
    public void use() {
        System.out.println("Product A1 is used.");
    }
}

// 具体产品类A2
public class ProductA2 extends ProductA {
    @Override
    public void use() {
        System.out.println("Product A2 is used.");
    }
}

// 抽象产品类B
public abstract class ProductB {
    public abstract void use();
}

// 具体产品类B1
public class ProductB1 extends ProductB {
    @Override
    public void use() {
        System.out.println("Product B1 is used.");
    }
}

// 具体产品类B2
public class ProductB2 extends ProductB {
    @Override
    public void use() {
        System.out.println("Product B2 is used.");
    }
}

// 抽象工厂类
public abstract class AbstractFactory {
    public abstract ProductA createProductA();

    public abstract ProductB createProductB();
}

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

    @Override
    public ProductB createProductB() {
        return new ProductB1();
    }
}

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

    @Override
    public ProductB createProductB() {
        return new ProductB2();
    }
}

// 测试代码
public class Client {
    public static void main(String[] args) {
        AbstractFactory factory1 = new ConcreteFactory1();
        ProductA productA1 = factory1.createProductA();
        productA1.use(); // Output: Product A1 is used.
        ProductB productB1 = factory1.createProductB();
        productB1.use(); // Output: Product B1 is used.

        AbstractFactory factory2 = new ConcreteFactory2();
        ProductA productA2 = factory2.createProductA();
        productA2.use(); // Output: Product A2 is used.
        ProductB productB2 = factory2.createProductB();
        productB2.use(); // Output: Product B2 is used.
    }
}