修复学员管理重复时新增报错

snowy-plugin/snowy-plugin-disk/snowy-plugin-disk-func/src/main/java/vip/xiaonuo/disk/controller/CourseStudentRelateController.java

@@ -147,7 +147,7 @@ public class CourseStudentRelateController {
         List<CourseStudentRelate> willAddList=new ArrayList<>();
         //先排查该课程要新关联的学生id中，是否已有某学生关联，存在的话进行剔除
         String[] userIds = courseStudentRelateAddParam.getUserIds().split(",");
-        List<String> willUserIdList= Arrays.asList(userIds);
+        List<String> willUserIdList= new ArrayList<>(Arrays.asList(userIds));
         param.put("courseId", courseStudentRelateAddParam.getCourseId());
         List<CourseStudentRelate> alreadyRelateList=courseStudentRelateService.listWrapper(param);
         List<String> alreadyRelateIdList=CollStreamUtil.toList(alreadyRelateList, CourseStudentRelate::getUserId);