fix bugs

stmms-biz/src/main/java/cn/com/qmth/stmms/biz/exam/service/impl/ExamStudentServiceImpl.java

@@ -231,10 +231,13 @@ public class ExamStudentServiceImpl extends BaseQueryService<ExamStudent> implem
     public ExamStudentSearchQuery findByQuery(final ExamStudentSearchQuery query) {
         checkQuery(query);
         if (query.getSheetCount() != null) {
-            query.setSheetCount(query.getSheetCount() / 2);
+            query.setSheetCount(query.getSheetCount() * 2);
         }
         Page<ExamStudent> result = studentDao.findAll(buildSpecification(query), query);
         fillResult(result, query);
+        if (query.getSheetCount() != null) {
+            query.setSheetCount(query.getSheetCount() / 2);
+        }
         return query;
     }