练习册bug修改

ssj-kmt-exercise-service-impl/src/main/java/com/ssj/service/kmt/kmt/service/impl/KmtExerciseServiceImpl.java

@@ -1687,11 +1687,16 @@ public class KmtExerciseServiceImpl implements KmtExerciseService {
     private List<ExerciseBookEditDto> sortByBookName (List<ExerciseBookEditDto> list){
         if (list != null){
             Map<String, List<ExerciseBookEditDto>> temp = new HashMap<>();
+            List<ExerciseBookEditDto> tmpList = null;
             for (ExerciseBookEditDto item : list){
                 if (temp.containsKey(item.getExerciseBookName())){
-                    temp.get(item.getExerciseBookName()).add(item);
+                    tmpList = temp.get(item.getExerciseBookName());
+                    tmpList.add(item);
+                    temp.put(item.getExerciseBookName(), tmpList);
                 } else {
-                    temp.put(item.getExerciseBookName(), Collections.singletonList(item));
+                    tmpList = new ArrayList<>();
+                    tmpList.add(item);
+                    temp.put(item.getExerciseBookName(), tmpList);
                 }
             }
             ArrayList tempList = new ArrayList(temp.keySet());