// 根据id去重

List<Person> unique = appleList.stream().collect(

collectingAndThen(

toCollection(() -> new TreeSet<>(comparingLong(Apple::getId))), ArrayList::new)

);

 

// 查找流中最大 最小值

Optional<Dish> maxDish = Dish.menu.stream().

collect(Collectors.maxBy(Comparator.comparing(Dish::getCalories)));

maxDish.ifPresent(System.out::println);

Optional<Dish> minDish = Dish.menu.stream().

collect(Collectors.minBy(Comparator.comparing(Dish::getCalories)));

minDish.ifPresent(System.out::println);

引自https://blog.csdn.net/lu930124/article/details/77595585

 

// 把对象本身当做value

public Map<Long, Account> getIdAccountMap(List<Account> accounts) {

return accounts.stream().collect(Collectors.toMap(Account::getId, account -> account));

}