方式一：使用String.join()

import java.util.ArrayList;
import java.util.List;
public class Main {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("apple");
        list.add("banana");
        list.add("cherry");
        String result = String.join(",", list);
        System.out.println(result); // 输出: apple,banana,cherry
    }
}

方式二：使用stream流

import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
public class Main {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        list.add("apple");
        list.add("banana");
        list.add("cherry");
        String result = list.stream().collect(Collectors.joining(","));
        System.out.println(result); // 输出: apple,banana,cherry
    }
}