Initial experience of annotation

1. Definition notes

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Person {

    String name() default "abc";
    int age() default 20;
}

2. Using annotations

public class Student {
    @Person(name = " king xx",age = 30)
    public Object person;
}

3. Handle comments

public class PersonUtils {
    public static void getPersonInfo(Class<?> clazz){
        for (Field declaredField : clazz.getDeclaredFields()) {
            if (declaredField.isAnnotationPresent(Person.class)){
                Person person = declaredField.getAnnotation(Person.class);
                System.out.println("name:"+person.name()+"age"+person.age());
            }
        }
    }
}

4. test

PersonUtils.getPersonInfo(Student.class);

5. result