从枚举创建单例 bean

Question

我有一个如下所示的枚举

public enum MyBeanType {
  Type1,
  Type2
  ...
  Type100;
}

我想为每个枚举值创建一个 Bean。

public Class MyBean {
  private MyBeanType type;

 public MyBean(MyBeanType type) { this.type = type; }
}

我知道我可以像这样在我的配置中列出每一个：

@Configuration
public class MyBeanConfig() {

  @Bean public MyBean myBeanType1() { return new MyBean(MyBeanType.Type1);
  @Bean public MyBean myBeanType2() { return new MyBean(MyBeanType.Type2);
  ... 
  @Bean public MyBean myBeanType100() { return new MyBean(MyBeanType.Type100);  

}

但是有没有办法更动态地做到这一点？我通常将所有这些连接为 List，但在某些情况下我也想通过名称连接 myBeanType2。

Answer 1

您可以简单地以编程方式注册 bean。像这样的东西应该可以做到。

@Configuration
public class MyBeanConfig() implements ApplicationContextAware {

    @Override
    public void setApplicationContext(final ApplicationContext ctx) {

        final ConfigurableListableBeanFactory beanFactory = ((ConfigurableApplicationContext) ctx).getBeanFactory();

        for(final MyBeanType beanType: MyBeanType.values()) {

            beanFactory.registerSingleton(MyBean.class.getCanonicalName() + "_" + beanType, new MyBean(beanType));
        }
    }
}

Answer 2

编写一个自定义 BeanFactoryPostProcessor 来使用 bean 定义。

@Bean
public BeanFactoryPostProcessor getBeanFactoryPostProcessor() {
  return beanFactory -> {
    for (int i = 0; i < MyBeanType.values().length; i++) {
      beanFactory.registerSingleton(MyBeanType.class.getSimpleName() + i, 
        new MyBean(MyBeanType.values()[i]));
    }
  };
}

从枚举创建单例 bean

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