Map<String, List<YourBean>> mapBy= list.stream().collect(
Collectors.groupingBy(i -> i.getPriceId() + i.getId(), Collectors.toList()));
Map<String, List<YourBean>> mapBy= list.stream().collect(
Collectors.groupingBy(i -> i.getPriceId() + i.getId(), Collectors.toList()));
前提條件:jdk1.8之後使用 public class CollectionTest { public static void main(String[] args) { Collection<