java - Spring:在基于注释的配置期间在@import 文件中引用bean

Question

我有两个 spring 配置类 A 和 B。B 中的 beans 使用 @import 注释导入到 A 中，就像这样

@Configuration
@Import({B.class})
public class A {
    private BBean bbean;

    @Bean
    public ABean aBean() {
        // need to reference B's bean over here
        return aBean()// after referencing B's bean
    }
}

@Configuration
public class B {
    @Bean
    public BBean bBean(){
       return new BBean();        
    }
}

在创建 bean aBean 时如何引用 bean bBean？有人会认为 @Required 或 @Autowired 可以在这里工作，但它不会:(

更新 - 我在这里尝试做的是使用 TestNG 和 maven 运行单元测试。当我尝试引用“Autowired”bean 时，maven 挂起，可能处于无限循环或等待加载 bean。

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running TestSuite
13:15:42,427  INFO eans.factory.xml.XmlBeanDefinitionReader: 315 - Loading XML bean definitions from class path resource [META-INF/spring/app-context.xml]
13:15:42,589  INFO nnotation.ClassPathBeanDefinitionScanner: 210 - JSR-330 'javax.inject.Named' annotation found and supported for component scanning
13:15:42,671  INFO ontext.support.GenericApplicationContext: 495 - Refreshing org.springframework.context.support.GenericApplicationContext@45d6a56e: startup date [Fri Feb 15 13:15:42 PST 2013]; root of context hierarchy
13:15:42,769  INFO ctory.support.DefaultListableBeanFactory: 623 - Overriding bean definition for bean 'dataSource': replacing [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=repositoryConfig; factoryMethodName=dataSource; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [com/abc/pagg/ddee/repository/config/RepositoryConfig.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=serviceConfig; factoryMethodName=dataSource; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [com/abc/pagg/ddee/service/config/ServiceConfig.class]]
13:15:42,983  INFO ion.AutowiredAnnotationBeanPostProcessor: 139 - JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
13:15:43,027  INFO ctory.support.DefaultListableBeanFactory: 557 - Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@66b51404: defining beans [org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,serviceConfig,org.springframework.aop.config.internalAutoProxyCreator,org.springframework.transaction.annotation.AnnotationTransactionAttributeSource#0,org.springframework.transaction.interceptor.TransactionInterceptor#0,org.springframework.transaction.config.internalTransactionAdvisor,transactionManager,sqlSessionFactory,org.mybatis.spring.mapper.MapperScannerConfigurer#0,org.springframework.context.annotation.ConfigurationClassPostProcessor$ImportAwareBeanPostProcessor#0,commonConfig,propertiesConfig,repositoryConfig,iusRestManager,localCacheClientAdapter,memcachedClientAdapter,s3Adapter,dataSource,userMapper]; root of factory hierarchy  <<--- hangs right here

更新 - 此处为真实代码

@Configuration
@Import({CommonConfig.class})
public class ServiceConfig {
private final Logger log = LoggerFactory.getLogger(ServiceConfig.class);
private org.apache.commons.configuration.Configuration propertiesConfig;

@Autowired
public void setPropertiesConfig(org.apache.commons.configuration.Configuration propertiesConfig){
    this.propertiesConfig = propertiesConfig;
}

public ServiceConfig() {
}

@Bean
public DataSource dataSource() {
    final BasicDataSource dataSource = new BasicDataSource();
 --->   dataSource.setDriverClassName(propertiesConfig.getString("jdbc.driver")); <----
    //dataSource.setUrl(propertiesConfig.getString("jdbc.url"));
    //dataSource.setUsername(propertiesConfig.getString("jdbc.username"));
    //dataSource.setPassword(propertiesConfig.getString("jdbc.password"));

    return dataSource;
}

bean propertiesConfig 在 CommonConfig 中定义。由于 propertiesConfig 为空，我在突出显示的行上收到了一个 invocationTargetException。 dataSource bean 不断在循环中被实例化。

Answer 1

@Import 的文档提到在您描述的情况下您应该使用 @Autowired:

@Bean definitions declared in imported @Configuration classes should be accessed by using @Autowired injection. Either the bean itself can be autowired, or the configuration class instance declaring the bean can be autowired. The latter approach allows for explicit, IDE-friendly navigation between @Configuration class methods.