在java8 streams中使用分组依据

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class Main {
    public static void main(String[] args) {
        List<String> fruits = Arrays.asList("apple", "banana", "orange", "apple", "orange");

        // 根据水果的首字母进行分组
        Map<Character, List<String>> groupedFruits = fruits.stream()
                .collect(Collectors.groupingBy(fruit -> fruit.charAt(0)));

        // 输出分组结果
        groupedFruits.forEach((key, value) -> System.out.println(key + ": " + value));
    }
}

a: [apple, apple]
b: [banana]
o: [orange, orange]