add 乐团学生列表增加，声部更换详情

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

@@ -344,7 +344,7 @@ public class SubjectChangeServiceImpl extends BaseServiceImpl<Integer, SubjectCh
                 subjectChange.setOriginalMusicalPrice(studentLastChange.getChangeMusicalPrice());
             }
 
-            if (studentLastChange.getChangeAccessories() != null) {
+            if (StringUtils.isNotBlank(studentLastChange.getChangeAccessories())) {
                 String[] goodsIdArr = studentLastChange.getChangeAccessories().split(",");
                 String accessoriesId = "";
                 for (String goodsId : goodsIdArr) {