Java自定义注解Annotation

定义注解：

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface MyAnnotation {

}

注解的使用：

public class AnnotationDemo {
    @MyAnnotation
    public void hasAnnotation() {
        System.out.println("hasAnnotation ?");
    }
}

测试：

public class AnnotationDemoTest {
    @Test
    public void test() {
        Method[] methods = AnnotationDemo.class.getDeclaredMethods();
        for (Method method : methods) {
            if (method.isAnnotationPresent(MyAnnotation.class)) {
                try {
                    method.invoke(new AnnotationDemo(), new Object[] {});
                }
                catch (IllegalArgumentException e) {
                    e.printStackTrace();
                }
                catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
                catch (InvocationTargetException e) {
                    e.printStackTrace();
                }
                System.out.println(" yes");
            }
        }
    }
}

运行输出结果：

hasAnnotation ?
yes