工厂模式

简单工厂模式

public interface ITea { 
// 沏茶 public void makeTea(); 
}

public class LongjingTea implements ITea {
    @Override
    public void makeTea() {
        System.out.println("西湖龙井");
    }
}

public class BiluochunTea implements ITea{
    @Override
    public void makeTea() {
        System.out.println("碧螺春");
    }
}

public class TeaFactory {

    public ITea createTea(String type){
        ITea tea = null;
        if(type.equals("longjing")){
            tea = new LongjingTea();
        }else if(type.equals("biluochun")){
            tea = new BiluochunTea();
        }
        if(tea != null){
            tea.makeTea();
        }
        return tea;
    }
}

工厂方法

public interface ITeaFactory { // 生产茶叶 public ITea createTea(); }


public class LongjingTeaFactory implements ITeaFactory{
    @Override
    public ITea createTea() {
        return new LongjingTea();
    }
}

public class BiluochunTeaFactory implements ITeaFactory{
    @Override
    public ITea createTea() {
        return new BiluochunTea();
    }
}
public class FactoryMethodTest {
    public static void main(String[] args) {
        ITeaFactory factory = new LongjingTeaFactory();
        factory.createTea();

        factory = new BiluochunTeaFactory();
        factory.createTea();
    }
}

如果要新增一种茶叶，比如毛尖，只需要新建一个生产毛尖的工厂类实现ITeaFactory即可。可以看到符合开闭原则、单一职责原则。

看下类图

抽象工厂

举例说明下，有两个工厂，美的、格力。这两个工厂都生产两种产品：冰箱和洗衣机。下面使用抽象工厂模式来描述每个工厂的两种产品的创建过程。

1、首先创建两个产品的接口类：

/**
 * 冰箱
 */
public interface IFridge {

    // 冷藏
    void coldStorage();
}

/**
 * 洗衣机
 */
public interface IWasher {
    void wash();
}

public class MeideFridge implements IFridge{
    @Override
    public void coldStorage() {
        System.out.println("美的冰箱");
    }
}

public class MeideWasher implements IWasher {
    @Override
    public void wash() {
        System.out.println("美的洗衣机");
    }
}

public class GeliFridge implements IFridge {
    @Override
    public void coldStorage() {
        System.out.println("格力冰箱");
    }
}

public class GeliWasher implements IWasher{
    @Override
    public void wash() {
        System.out.println("格力洗衣机");
    }
}

/**
 * 抽象工厂接口，家用电器工厂，生产冰箱和洗衣机
 */
public interface IHouseholdElectricFactory {

    IFridge createFridge();

    IWasher createWasher();
}

public class MeideHouseholdFactory implements IHouseholdElectricFactory{
    @Override
    public IFridge createFridge() {
        return new MeideFridge();
    }

    @Override
    public IWasher createWasher() {
        return new MeideWasher();
    }
}

public class GeliHouseholdFactory implements IHouseholdElectricFactory{
    @Override
    public IFridge createFridge() {
        return new GeliFridge();
    }

    @Override
    public IWasher createWasher() {
        return new GeliWasher();
    }
}