From 3aaa1f84ce45b085300d653ed910598b2e446964 Mon Sep 17 00:00:00 2001
From: luoweijian <1329394916@qq.com>
Date: Thu, 19 Mar 2026 16:15:42 +0800
Subject: [PATCH] bug

---
 .../impl/SubmitPaperDomainServiceImpl.java    | 22 ++++++++++++++-----
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/main/java/com/project/exam/domain/service/impl/SubmitPaperDomainServiceImpl.java b/src/main/java/com/project/exam/domain/service/impl/SubmitPaperDomainServiceImpl.java
index 785249a..430316e 100644
--- a/src/main/java/com/project/exam/domain/service/impl/SubmitPaperDomainServiceImpl.java
+++ b/src/main/java/com/project/exam/domain/service/impl/SubmitPaperDomainServiceImpl.java
@@ -126,11 +126,21 @@ public class SubmitPaperDomainServiceImpl implements SubmitPaperDomainService {
 
     private String formatAnswer(String ans) {
         if (StrUtil.isBlank(ans)) return "";
-        // 去空格 -> 转大写 -> 排序（解决 B,A vs A,B 的问题）
-        return Arrays.stream(ans.split(","))
-                .map(String::trim)
-                .map(String::toUpperCase)
-                .sorted()
-                .collect(Collectors.joining(","));
+
+        // 1. 去掉所有干扰字符：逗号、空格、分号、中英文逗号等
+        // 使用正则表达式替换掉所有非字母数字的字符
+        String cleanAns = ans.replaceAll("[^a-zA-Z0-9]", "");
+
+        // 2. 将字符串拆分为单个字符数组
+        // 例如 "AB" -> ["A", "B"], "A,B" -> ["A", "B"]
+        String[] chars = cleanAns.split("");
+
+        // 3. 流式处理：去重(可选) -> 转大写 -> 排序 -> 拼接
+        return Arrays.stream(chars)
+                .filter(StrUtil::isNotBlank)    // 过滤掉空字符串
+                .map(String::toUpperCase)        // 统一转大写
+                .distinct()                     // 如果用户不小心输入了 "A,A,B"，去重处理
+                .sorted()                       // 排序，保证 B,A 变 AB
+                .collect(Collectors.joining("")); // 拼接为 "AB"
     }
 }