Java8 Stream 集合根据对象属性去重

集合数据

List<ThirdStockJdBackupLibraryPo> list = new ArrayList<ThirdStockJdBackupLibraryPo>(){{
            add(new ThirdStockJdBackupLibraryPo("123","zs"));
            add(new ThirdStockJdBackupLibraryPo("123","ls"));
            add(new ThirdStockJdBackupLibraryPo("456","zl"));
        }};

需求：根据sku去重。

方式一

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


public static void main(String[] args) {   
        list.stream().filter(distinctByKey(b -> b.getSku()))
                .forEach(b -> System.out.println(b.getSku()+ "," + b.getProductName()));
    }

方式二

public static <T> Predicate<T> distinctByKey(Function<? super T, ?> keyExtractor) {
        Set<Object> seen = ConcurrentHashMap.newKeySet();
        return t -> seen.add(keyExtractor.apply(t));
    }
public static void main(String[] args) {
        list.parallelStream().filter(distinctByKey1(ThirdStockJdBackupLibraryPo::getSku))
                .forEach(System.out::println);
    }