枚举类与注解8-可重复注解（JDK8新特性）

可重复注解

1、方法

1）在MyAnnotation上声明@Repeateble，成员值为MyAnnotations.class

2）MyAnnotation的Target和Rentention，要与MyAnnotations相同

要使用的地方

@MyAnnotation(value ="Morning")

@MyAnnotation(value ="Good Night")

//JDK8之前，多注解写法

//@MyAnnotations({@MyAnnotation(value = "hello"),@MyAnnotation(value = "Hi")})

class Person {

private Stringname;

private int age;

public Person(String name,int age) {

this.name = name;

this.age = age;

}

......

}

MyAnnotations.class

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

import static java.lang.annotation.ElementType.*;

import static java.lang.annotation.ElementType.LOCAL_VARIABLE;

@Retention(RetentionPolicy.RUNTIME)

@Target({TYPE,FIELD,METHOD,PARAMETER,CONSTRUCTOR,LOCAL_VARIABLE})

public @interface MyAnnotations {

    MyAnnotation[] value();

}

MyAnnotation.class

import java.lang.annotation.*;

import static java.lang.annotation.ElementType.*;

@Inherited

@Repeatable(MyAnnotations.class)

@Retention(RetentionPolicy.RUNTIME)

@Target({TYPE,FIELD,METHOD,PARAMETER,CONSTRUCTOR,LOCAL_VARIABLE})

public @interface MyAnnotation {

    String value()default "Hello";

}