fix 学生作业曲目可用标记

mec-biz/src/main/java/com/ym/mec/biz/service/impl/StudentLessonTrainingDetailServiceImpl.java

@@ -251,8 +251,14 @@ public class StudentLessonTrainingDetailServiceImpl extends ServiceImpl<StudentL
                                 studentLessonTrainingDetail.setValidFlag(true);
                             }
 
+                            // 免费曲目也可以直接访问
+                            if (StringUtils.isBlank(sysMusicScore.getRankIds())) {
+                                studentLessonTrainingDetail.setValidFlag(true);
+                            }
+
                             // 用户VIP可查看曲目分类
-                            if (userVipMap.containsKey(studentLessonTrainingDetail.getUserId().intValue())) {
+                            if (Objects.nonNull(studentLessonTrainingDetail.getUserId())
+                                && userVipMap.containsKey(studentLessonTrainingDetail.getUserId().intValue())) {
 
                                 // 设置默认不可以查看
                                 boolean validFlag = false;