fix

zhongzheng-system/src/main/java/com/zhongzheng/modules/grade/service/impl/ClassGradeUserServiceImpl.java

@@ -2524,7 +2524,7 @@ public class ClassGradeUserServiceImpl extends ServiceImpl<ClassGradeUserMapper,
                         if (Validator.isNotEmpty(classPeriodSectionVo.getStudyEndTime()) && ChapterEndTime.longValue() < classPeriodSectionVo.getStudyEndTime().longValue()) {
                             ChapterEndTime = classPeriodSectionVo.getStudyEndTime();
                         }
-                        if (ChapterStartTime == 0L || ChapterStartTime.longValue() > classPeriodSectionVo.getStudyStartTime().longValue()) {
+                        if ((Validator.isNotEmpty(classPeriodSectionVo.getStudyStartTime())&&ChapterStartTime == 0L) || (Validator.isNotEmpty(classPeriodSectionVo.getStudyStartTime())&&ChapterStartTime.longValue() > classPeriodSectionVo.getStudyStartTime().longValue())) {
                             ChapterStartTime = classPeriodSectionVo.getStudyStartTime();
                         }
                     }