[英]Are Java meta-annotations available at runtime?
我创建了一个元注释并将其应用于注释,但无法找到任何方法来查找在运行时与注释关联的元注释。 这在JDK 6中是否真的受到支持?
例如:
/**
* Meta-annotation for other annotations declaring them to be "filter" annotations
*/
@Target(ElementType.ANNOTATION_TYPE) // make this a meta-annotation
@Retention(RetentionPolicy.RUNTIME) // available at runtime
public @interface Filter
{
}
/**
* Marks a test as only being applicable to TypeOne clients
*/
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Filter
public @interface TypeOne
{
}
public class MyClientClass
{
// Would like to scan this method to see if the method has an Annotation that is of meta-type "Filter"
@TypeOne
public void testMethod()
{
}
}
找到带有“TypeOne”注释的方法很简单,但是一旦掌握了Annotation,我怎样才能在运行时找出该注释是否具有相关的元注释(即“过滤器”)?
我的答案已经很抱歉:
annotation.annotationType().isAnnotationPresent(Filter.class)
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