Java8-Stream流操作List去重问题

ArrayList<LabelInfoDTO> collect = labelInfoDTOS.stream().
collect(Collectors.collectingAndThen(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(LabelInfoDTO::getLabelCode))), ArrayList::new));

@NoArgsConstructor
@AllArgsConstructor
@Data
class Book {
 
    public static Book of(Long id, String name, String createTime) {
        return new Book(id, name, Date.from(LocalDateTime.parse(createTime, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")).atZone(ZoneId.systemDefault()).toInstant()));
    }
 
    private Long id;
 
    private String name;
 
    private Date createTime;
}

List<Book> books = new ArrayList<>();
books.add(Book.of(1L, "Thinking in Java", "2021-06-29 17:13:14"));
books.add(Book.of(2L, "Hibernate in action", "2021-06-29 18:13:14"));
books.add(Book.of(3L, "Thinking in Java", "2021-06-29 19:13:14"));

class Book {
    ...
 
    @Override
    public String toString() {
        return String.format("(%s,%s,%s)", id, name, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss").format(createTime.toInstant().atZone(ZoneId.systemDefault()).toLocalDateTime()));
    }
 
    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Book book = (Book) o;
        return Objects.equals(name, book.name);
    }
}
 
List<Book> distinctNameBooks1 = books.stream().distinct().collect(Collectors.toList());
System.out.println(distinctNameBooks1);

List<Book> distinctNameBooks2 = books.stream().collect(Collectors.collectingAndThen(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(o -> o.getName()))), ArrayList::new));
System.out.println(distinctNameBooks2);

public static <T> Predicate<T> distinctByKey(Function<? super T, Object> keyExtractor) {
    Map<Object, Boolean> map = new HashMap<>();
    return t -> map.putIfAbsent(keyExtractor.apply(t), Boolean.TRUE) == null;
}
 
List<Book> distinctNameBooks3 = books.stream().filter(distinctByKey(o -> o.getName())).collect(Collectors.toList());
System.out.println(distinctNameBooks3);

Map<Object, Boolean> map = new HashMap<>();
List<Book> distinctNameBooks4 = books.stream().filter(i -> map.putIfAbsent(i.getName(), Boolean.TRUE) == null).collect(Collectors.toList());
System.out.println(distinctNameBooks4);