在spring 中使用自定义注解

spring加载自定义注解的条件

只要注解实现@Component

spring 中的源码如下：

protected void registerDefaultFilters() {
//只扫描含有Component注解的类
this.includeFilters.add(new AnnotationTypeFilter(Component.class));
ClassLoader cl = ClassPathScanningCandidateComponentProvider.class.getClassLoader();
try {
this.includeFilters.add(new AnnotationTypeFilter(((Class<? extends Annotation>) ClassUtils.forName("javax.annotation.ManagedBean", cl)), false));
}catch (ClassNotFoundException ex) {
}
try {
this.includeFilters.add(new AnnotationTypeFilter(((Class<? extends Annotation>) ClassUtils.forName("javax.inject.Named", cl)), false));
logger.debug("JSR-330 'javax.inject.Named' annotation found and supported for component scanning");
}
catch (ClassNotFoundException ex) {
// JSR-330 API not available - simply skip.
}
}

从上面的源码中可以看到，只要一个注解类实现@Componet，Spring就可以扫描到容器中。

spring ApplicationContextAware接口

当一个类实现了这个接口（ApplicationContextAware）之后，这个类就可以方便获得ApplicationContext中的所有bean。

@Component
public class SpringContextHelper implements ApplicationContextAware {
private static ApplicationContext context = null;
@Override
public void setApplicationContext(ApplicationContext applicationContext)
throws BeansException {
context = applicationContext;
}
public static Object getBean(String name){
return context.getBean(name);
}
}