如何让 Collectors.groupingBy() 返回排序后的 LinkedHashMap？

Question

For example, I have a List:

{Cat, Cat, Cat, Dog, Dog, Rat}

I want to return a sorted Map, in ascending or descending at my choice, where the keys are the animal names, and the values are their appearance times.

For example

{
    Rat: 1
    Dog: 2
    Cat: 3
}

By using

LinkedHashMap<String, Long> map = 
    list
    .stream()                              
    .collect(Collectors.groupingBy(Function.identity(), LinkedHashMap::new, Collectors.counting()));

I can have a LinkedHashMap , but it is not sorted.

I know that I can sort the Map afterward, but is there a way to do it in one stream?

Thanks!

Answer 1

add sorted() operator:

LinkedHashMap<String, Long> result = Arrays.stream(array)
                .sorted()
                .collect(Collectors.groupingBy(Function.identity(), LinkedHashMap::new, Collectors.counting()));