文章目录
- EXP List
- 场景一 Object是已知对象,单纯去某一个成员变量为List<~>
- 场景二 Object其实String,但是强转感觉很LOW
- List中使用stream() 实现大小写转换
- 场景一 Object其实是String
- 场景二 Object是对象
EXP List 转List
场景一 Object是已知对象,单纯去某一个成员变量为List<~>
public class Main {public static void main(String[] args) {List list = new ArrayList<>();list.add(new Person("张三", 1));list.add(new Person("李四", 2));// 这里只需要idList ids = list.stream().map(Person::getId()).collect(Collectors.toList());}@Dataclass Person {private String name;private Long id;public Person(String name, String id) {this.name = name;this.id = id;}}
}
场景二 Object其实String,但是强转感觉很LOW
public class Main {public static void main(String[] args) {List
List中使用stream() 实现大小写转换
场景一 Object其实是String
public class Main {public static void main(String[] args) {List
场景二 Object是对象
public class Main {public static void main(String[] args) {List list = new ArrayList<>();list.add(new Person("A", 1));list.add(new Person("B", 2));// 这里只需要idList names = list.stream().map(item -> item.getName().toLowerCase(Locale.ROOT)).collect(Collectors.toList());}@Dataclass Person {private String name;private Long id;public Person(String name, String id) {this.name = name;this.id = id;}}
}