public class LinkedHashSetTest02 { public static void main(String[] args) {
LinkedHashSet<Character> lhs = new LinkedHashSet<>();
Scanner sc= new Scanner(System.in);
System.out.println("请输入一个字符串");
String s = sc.next(); for (int i = 0; i < s.length(); i++) { char[] chs = s.toCharArray();
lhs.add(chs);
}