前言

下面的示例展示了 SpringBoot 中如何使用工厂模式，该示例通过 ApplicationContext 直接获取 Spring 容器中所有 Animal 的 Bean，然后将它们存储在 animalMap 中，使用时直接从 Map 中获取实例。

另一种工厂模式可参考我另一篇文章 ：SpringBoot 工厂模式自动注入到Map

一、建立父类

java">public abstract class Animal {public abstract void makeSound();public abstract String getType();
}

二、两个子类

java">@Component
public class Cat extends Animal {@Overridepublic void makeSound() {System.out.println("Miao!");}@Overridepublic String getType() {return "cat";}
}

java">@Component
public class Dog extends Animal {@Overridepublic void makeSound() {System.out.println("Wang!");}@Overridepublic String getType() {return "dog";}
}

三、工厂类注入到 map 里

java">@Component
public class AnimalFactory implements ApplicationContextAware, InitializingBean {private final Map<String, Animal> animalMap = new ConcurrentHashMap<>();private ApplicationContext appContext;public Animal getAnimal(String animalType) {Animal animal = this.animalMap.get(animalType);if (animal == null) {throw new IllegalArgumentException("Unsupported animal type: " + animalType);}return animal;}@Overridepublic void afterPropertiesSet() throws Exception {Map<String, Animal> beansOfType = this.appContext.getBeansOfType(Animal.class);beansOfType.values().forEach(animal -> animalMap.put(animal.getType(), animal));}@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.appContext = applicationContext;}
}

四、测试

java">@Autowiredprivate AnimalFactory animalFactory;public void printSound() throws Exception {Animal animal_1 = animalFactory.getAnimal("dog");animal_1.makeSound(); // 输出 "Wang!"Animal animal_2 = animalFactory.getAnimal("cat");animal_2.makeSound(); // 输出 "Miao!"}