Java8中Stream流式处理案例

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

public class Test3 {

    public static void main(String[] args) {

        List<String> list = new ArrayList<>();
        list.add("CC");
        list.add("BB");
        list.add("DD");

        String out = list.stream().collect(Collectors.joining(","));

        System.out.println(out);

    }
}

CC,BB,DD