Java Stream - 如何collect带有分隔符的字符串的整数列表

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

public class Main {
  public static void main(String[] argv) {
    List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7);

    System.out.println(numbers.stream().map(number -> String.valueOf(number))
        .collect(Collectors.joining(", ")));
  }
}