找出字符串中第一个只出现一次的字符

import java.util.HashMap;
import java.util.Scanner;

/**

• 作者：李涵林

• /
  public class Main26 {

  public static void main(String[] args) {

    Scanner scanner = new Scanner(System.in);
  
    outer:while (scanner.hasNext()) {
        String nextLine = scanner.nextLine();
        char[] chars = nextLine.toCharArray();
        HashMap<Character, Integer> hashMap = new HashMap();
        for (int i = 0; i < chars.length; i++) {
            char aChar = chars[i];
            if (hashMap.containsKey(aChar)) {
                hashMap.put(aChar, hashMap.get(aChar) + 1);
            } else {
                hashMap.put(aChar, 1);
            }
        }
  
        for (int i = 0; i < chars.length; i++) {
            char aChar = chars[i];
            if (hashMap.get(aChar) == 1) {
                System.out.println(aChar);
                continue outer;
            }
        }
        System.out.println(-1);
    }

  }
  }