Java 自定义注解释义

package annotation;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;//RUNTIME表示运行时Person注解也存在//@Retention(RetentionPolicy.CLASS)@Retention(RetentionPolicy.RUNTIME)@interface Person {String name();int age();}@Person(name="Tom",age=20)class Test1{}@Person(name="Jack",age=22)class Test2{}//@Person(name="Anna",age=18)class Test3{}public class AnnotationTest{public static void printClassInto(Class c){System.out.print(c.getName()+". ");Person person = (Person) c.getAnnotation(Person.class);if (person!=null) {System.out.println("Person: "+person.name()+" ,age:"+person.age());}else {System.out.println("unknown person");}}public static void main(String[] args) {printClassInto(Test1.class);printClassInto(Test2.class);printClassInto(Test3.class);}}