java8 将一个 List<String> 转化为 指定字符分隔的字符串

#使用String.join() 工具类

List<String> strings = new ArrayList<>();
        strings.add("id");
        strings.add("name");
        strings.add("sex");`

String join = String.join(",", strings);
//输出结果是：id，name，sex

 

#使用Java8 Stream 流

List cities = Arrays.asList( "Milan", "London", "New York", "San Francisco");

String citiesCommaSeparated = cities.stream() .collect(Collectors.joining(","));

System.out.println(citiesCommaSeparated);