【fix空指针】

src/main/java/com/zzsn/event/service/impl/SysDictItemServiceImpl.java

@@ -12,6 +12,7 @@ import org.apache.commons.collections4.CollectionUtils;
 import org.apache.commons.collections4.MapUtils;
 import org.springframework.stereotype.Service;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
@@ -72,6 +73,9 @@ public class SysDictItemServiceImpl extends ServiceImpl<SysDictItemMapper, SysDi
     @Override
     public List<DictTreeVO> dictItemTreeList(List<String> dictIds) {
         List<DictTreeVO> itemList = baseMapper.dictItemList(dictIds);
+        if (CollectionUtils.isEmpty(itemList)) {
+            return new ArrayList<>();
+        }
         List<DictTreeVO> tree = TreeUtil.tree(itemList, "0");
         tree.forEach(e -> e.setPid(e.getDictId()));
         return tree;