使用StringJoiner拼接字符串

##使用StringJoiner拼接字符串

    // 字符串拼接
    // 将List<String> 拼接成 a,b,c字符串
    List<String> list = Arrays.asList("a", "b", "c");
    // StringJoiner
    StringJoiner stringJoiner = new StringJoiner(",");
    for (String str : list) {
        stringJoiner.add(str);
    }
    System.out.println("StringJoiner:" + stringJoiner.toString());
    // StringJoiner 带前缀和后缀
    StringJoiner stringJoiner1 = new StringJoiner(",", "{", "}");
    for (String str : list) {
        stringJoiner1.add(str);
    }
    System.out.println("StringJoiner 带前缀和后缀:" + stringJoiner1.toString());