如何计算文本文件中的单词，java 8风格

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

public class WordCount {
    public static void main(String[] args) {
        String filePath = "path/to/your/file.txt";

        try (BufferedReader reader = new BufferedReader(new FileReader(filePath))) {
            String line;
            Pattern pattern = Pattern.compile("\\W+");
            Map<String, Long> wordCountMap = reader.lines()
                    .flatMap(pattern::splitAsStream)
                    .map(String::toLowerCase)
                    .collect(Collectors.groupingBy(word -> word, Collectors.counting()));

            for (Map.Entry<String, Long> entry : wordCountMap.entrySet()) {
                System.out.println(entry.getKey() + ": " + entry.getValue());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}