离线报错null

examcloud-core-oe-admin-service/src/main/java/cn/com/qmth/examcloud/core/oe/admin/service/impl/ExamRecordServiceImpl.java

@@ -819,7 +819,9 @@ public class ExamRecordServiceImpl implements ExamRecordService {
 
         //每次考试持续时间
         if (info.getStartTime() != null && info.getEndTime() != null) {
-            info.setExamTime(info.getUsedExamTime() > 0 ? DateUtils.diff(info.getUsedExamTime()) : "");
+            if (info.getUsedExamTime() != null) {
+                info.setExamTime(info.getUsedExamTime() > 0 ? DateUtils.diff(info.getUsedExamTime()) : "");
+            }
         } else {
             info.setExamTime("");
         }