fix

mec-application/src/main/java/com/ym/mec/student/controller/StudentManageController.java

@@ -285,14 +285,16 @@ public class StudentManageController extends BaseController {
             }
 
             List<Integer> instrumentIdsBySubjectId = instrumentService.getInstrumentIdsBySubjectId(StringUtils.join(integers,","));
-            Map<Integer, InstrumentWrapper.Instrument> mapByIds = instrumentService.getMapByIds(instrumentIdsBySubjectId);
-            Map<Integer,String> extInstrumentNamesMap = new HashMap<Integer, String>();
-            mapByIds.forEach((k,v)->{
-                if (v !=null) {
-                    extInstrumentNamesMap.put(k, v.getName());
-                }
-            });
-            student.setExtInstrumentNamesMap(extInstrumentNamesMap);
+            if (CollectionUtils.isNotEmpty(instrumentIdsBySubjectId)) {
+                Map<Integer, InstrumentWrapper.Instrument> mapByIds = instrumentService.getMapByIds(instrumentIdsBySubjectId);
+                Map<Integer, String> extInstrumentNamesMap = new HashMap<Integer, String>();
+                mapByIds.forEach((k, v) -> {
+                    if (v != null) {
+                        extInstrumentNamesMap.put(k, v.getName());
+                    }
+                });
+                student.setExtInstrumentNamesMap(extInstrumentNamesMap);
+            }
         }