想问一下我想把一个单词的首尾字母大小写反转怎么实现用到什么方法吗

Question

想问一下我想把一个单词的首尾字母大小写反转怎么实现用到什么方法吗

Answer 1

         String str = "App";
        String[] split = str.split("");

        for (int i = 0; i < split.length; i++) {
            char chr = str.charAt(i);
            if ( i == 0 || i == split.length - 1) {
                if (Character.isUpperCase(chr)) {
                    String s = String.valueOf(chr);
                    split[i] = s.toLowerCase(Locale.ROOT);
                } else if (Character.isLowerCase(chr)) {
                    String s = String.valueOf(chr);
                    split[i] = s.toUpperCase(Locale.ROOT);
                }
            }
        }

        StringBuilder sb = new StringBuilder();
        for (String s : split) {
            sb.append(s);
        }

        System.out.println(sb);