fix

examcloud-core-questions-service/src/main/java/cn/com/qmth/examcloud/core/questions/service/impl/PaperDetailUnitServiceImpl.java

@@ -85,7 +85,7 @@ public class PaperDetailUnitServiceImpl implements PaperDetailUnitService {
                 for(int i=0;i<sarr.length;i++) {
                     sarr[i]=String.valueOf(question.getQuesAnswer().charAt(i));
                 }
-                question.setQuesAnswer((StringUtils.join(sarr, ",")));
+                question.setQuesAnswer(StringUtils.join(sarr, ","));
             }
         }