// 数据去重 利用原理 map去重
List noRepeatList = bookList.stream.filter(distinctByKey(Book::getName)).collect(Collectors.toList());`

/**
 * 数据流去重方法
 * 如果多个参数，使用添加即可
 * @param keyExtractor
 * @param <T>
 * @return
 */
public 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;
}