ImportSelector使用
2018-08-23 本文已影响0人
莫看烟雨
ImportSelector就比较牛逼了,可以读取annotation的属性来决定要加载哪些Configuration。
以下为ImportSelector的接口定义:
/**
* Interface to be implemented by types that determine which @{@link Configuration}
* class(es) should be imported based on a given selection criteria, usually one or more
* annotation attributes.
*
* <p>An {@link ImportSelector} may implement any of the following
* {@link org.springframework.beans.factory.Aware Aware} interfaces, and their respective
* methods will be called prior to {@link #selectImports}:
* <ul>
* <li>{@link org.springframework.context.EnvironmentAware EnvironmentAware}</li>
* <li>{@link org.springframework.beans.factory.BeanFactoryAware BeanFactoryAware}</li>
* <li>{@link org.springframework.beans.factory.BeanClassLoaderAware BeanClassLoaderAware}</li>
* <li>{@link org.springframework.context.ResourceLoaderAware ResourceLoaderAware}</li>
* </ul>
*
* <p>ImportSelectors are usually processed in the same way as regular {@code @Import}
* annotations, however, it is also possible to defer selection of imports until all
* {@code @Configuration} classes have been processed (see {@link DeferredImportSelector}
* for details).
*
* @author Chris Beams
* @since 3.1
* @see DeferredImportSelector
* @see Import
* @see ImportBeanDefinitionRegistrar
* @see Configuration
*/
public interface ImportSelector {
/**
* Select and return the names of which class(es) should be imported based on
* the {@link AnnotationMetadata} of the importing @{@link Configuration} class.
*/
String[] selectImports(AnnotationMetadata importingClassMetadata);
}
selectImports方法的返回值为Configuration主类的全类名。
使用方法和ImportBeanDefinitionRegistrar类似,也是通过import来引入生效的。
举例如下:
@SpringBootApplication
@ComponentScan
@RestController
@EnableConfigurationProperties(RedisProp.class)
@Import(DataConfig3.class)
public class TestApplication
public class DataConfig3 implements ImportSelector{
@Override
public String[] selectImports(AnnotationMetadata importingClassMetadata) {
return new String[]{DataConfig.class.getName()};
}
}