遍历字符串每个字符

   public static void main(String[] args) {
        String str = "123\\n456\\n789\\n+0- qwertyuiopasdfghjklzxcvbnm是谁？！@#";
        for (int i = 0; i < str.length(); i++) {
            System.out.println(str.charAt(i));
        }
    }