98-hands-on
1. 函数对象
![image-20240415205750369](http://listao.cn:10000/i/0/2024/04/15/205752-0.webp)
- 生成匿名类的对象名
![image-20240415210112103](http://listao.cn:10000/i/0/2024/04/15/210113-0.webp)
1. 方法引用
![image-20240416092251211](http://listao.cn:10000/i/0/2024/04/16/092253-0.webp)
2. Collection抽取一个字段
Stream<Ooxx> ooxxStream = Stream.of(new Ooxx(), new Ooxx(), new Ooxx());
Set<Integer> ids = ooxxStream.map(Ooxx::getId).collect(Collectors.toSet());
Stream<Ooxx> ooxxStream = Stream.of(new Ooxx(), new Ooxx(), new Ooxx());
Set<Integer> ids = ooxxStream.map(Ooxx::getId).collect(Collectors.toSet());