动态向Spring容器注入Bean

• 1、执行注入工具类
• 2、容器启动读取配置文件并调用注入方法
• 3、配置类详情
• 4、配置文件详情

@Component
public class ApplicationContextUtil implements ApplicationContextAware {

    private static ApplicationContext applicationContext;

    
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) {
        ApplicationContextUtil.applicationContext = applicationContext;
    }
    
    public static Boolean isBeanExit(String beanName) {
        try {
            applicationContext.getBean(beanName);
        } catch (Exception e) {
            return false;
        }
        return true;
    }
    
    public static Object registerSingletonBean(String beanName, Object singletonObject) {
        //将applicationContext转换为ConfigurableApplicationContext
        ConfigurableApplicationContext configurableApplicationContext = (ConfigurableApplicationContext) applicationContext;
        //获取BeanFactory
        DefaultListableBeanFactory defaultListableBeanFactory = (DefaultListableBeanFactory) configurableApplicationContext.getAutowireCapableBeanFactory();
        //动态注册bean.
        defaultListableBeanFactory.registerSingleton(beanName, singletonObject);
        //获取动态注册的bean.
        return configurableApplicationContext.getBean(beanName);
    }
}

@Component
@Slf4j
public class AliyunDbFactory implements ApplicationListener {
    private final CloudDbProperties cloudDbProperties;

    public AliyunDbFactory(CloudDbProperties cloudDbProperties) {
        this.cloudDbProperties = cloudDbProperties;
    }

    @Override
    public void onApplicationEvent(ContextRefreshedEvent contextRefreshedEvent) {
        for (AliyunDb aliyun : cloudDbProperties.getAliyuns()) {
            //根据配置文件内容，构建bean，并注入
            ApplicationContextUtil.registerSingletonBean("beanName", new Object());
        }
    }
}

@Getter
@Setter
@Configuration
@ConfigurationProperties(prefix = "xx.yy.zz")
public class CloudDbProperties {

    private List aliyuns;
    @Getter
    @Setter
    @ToString
    public static class AliyunDb implements Serializable {
        private String companyId;
        private String ecsAccessKeyId;
        private String ecsAccessSecret;
    }
}

xx:
  yy:
    zz:
      aliyuns:
        - company-id: 123
          ecs-access-key-id: LTAI4Fmb3HCMWN59T7v2MBSD
          ecs-access-secret: 4DbnjVGr7DQ1wWzForWppTzAUk6ppf
        - company-id: 456
          ecs-access-key-id: XXXXXXXXXXXXXX
          ecs-access-secret: YYYYYYYYYYYYYYYY