java - AnnotationConfigApplicationContext 尚未使用 ApplicationContextAware 刷新

Question

我在非 Spring 框架中使用 Spring beans，为此我已经实现了 ApplicationContextAware 来访问 spring beans。

@Service
public class ApplicationContextProviderService implements ApplicationContextAware {
    private static ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        ApplicationContextProviderService.applicationContext = applicationContext;
    }

    public static <T> T getBean(Class<T> beanType) {
        System.out.println("bean out: " + applicationContext);
        return applicationContext.getBean(beanType);
    }

}

我尝试从非 Spring 类访问 Spring 服务:ConnectionStateService:

this.connectionStateService = ApplicationContextProviderService.getBean(ConnectionStateService.class);

我收到以下错误:

java.lang.IllegalStateException:
**org.springframework.context.annotation.AnnotationConfigApplicationContext@7f485fda has not been refreshed yet     at
** org.springframework.context.support.AbstractApplicationContext.assertBeanFactoryActive(AbstractApplicationContext.java:1072) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]   at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1102) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]   at com.example.app.service.ApplicationContextProviderService.getBean(ApplicationContextProviderService.java:19) ~[classes/:na]  at com.example.app.CustomFilter.<init>(CustomFilter.java:26) ~[classes/:na]

如何解决这个问题？

Answer 1

当应用程序在应用程序运行之前尝试调用 ApplicationContext 时，就会出现此问题，因此您将无法拥有应用程序上下文，因为它尚未创建。解决方案是为 ConnectionStateService 类创建一个单例，这样您就不需要创建用于调用 ApplicationContext 的服务。

public class ConnectionStateService { 

// static variable instance of type Singleton 
private static ConnectionStateService single_instance = null; 

// private constructor restricted to this class itself 
private ConnectionStateService() { 
 // some stuffs for initialize here
}  

// static method to create instance of Singleton class 
public static ConnectionStateService getInstance()  { 
if (instance == null) 
     instance = new ConnectionStateService(); 
     return instance; 
} 

}