java8用Stream对List＜Map＜String,Object＞＞进行去重

方法1:list.stream().collect(Collectors.collectingAndThen(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(m -> m.get("id").toString()))), ArrayList::new

小烧包包

1185人浏览 · 2022-04-21 17:31:57

小烧包包 · 2022-04-21 17:31:57 发布

方法1:

list.stream().collect(
        Collectors.collectingAndThen(
                Collectors.toCollection(
                        () -> new TreeSet<>(Comparator.comparing(m -> m.get("id").toString()))
                ), ArrayList::new
        )
);

方法2:

public class StreamEx {
    public static <T> Predicate<T> distinctByKey(Function<? super T, Object> keyExtractor) {
        Map<Object, Boolean> seen = new ConcurrentHashMap<>();
        return t -> seen.putIfAbsent(keyExtractor.apply(t), Boolean.TRUE) == null;
    }
}




list.stream().filter(StreamEx.distinctByKey(x -> 
 x.get("id"))).collect(Collectors.toList());