jdk8根据字段去重

集合listUsers

方法1：

 List<Users> distinctUsers = listUsers.stream()

               .collect(Collectors.collectingAndThen

                       (Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(t -> t.getSno()))), ArrayList::new)

               );

方法2：

List<Users> distinctUsers = listUsers.stream().filter(distinctByKey(Users::getSno)).collect(Collectors.toList());

public static <T> Predicate<T> distinctByKey(Function<? super T, Object> keyExtractor) {

       Map<Object, Boolean> seen = new ConcurrentHashMap<>();

       return object -> seen.putIfAbsent(keyExtractor.apply(object), Boolean.TRUE) == null;

   }

顶

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