如何在java 8中的单行中将列表的元素处理为另一个列表

Question

There is a list of View2 object, I want to add the Id of View2 object in List<Integer> Ids . I want to process the above operation in a single line of code.

class View1{
  List<Integer> Ids;
}
class View2{
  Integer Id;
}

List<View2> views2 = getViews()

Want to something like following.

view1.setIds(view2.forEach(s -> s.getId()));

Answer 1

尝试这个

 view1.setIds(view2.stream().map(View2::getId).collect(Collectors.toList()));