fix bug

sxz-base/src/main/java/com/fdkk/sxz/util/readFloorplan.java

@@ -1,6 +1,7 @@
 package com.fdkk.sxz.util;
 
 
+import cn.hutool.core.util.ObjectUtil;
 import com.alibaba.fastjson.JSONArray;
 import com.alibaba.fastjson.JSONObject;
 
@@ -183,8 +184,10 @@ public class readFloorplan {
             JSONObject start = jsonPoints.getJSONObject(startPointId);
             JSONObject end = jsonPoints.getJSONObject(endPointId);
 
+
             JSONObject startParent = start.getJSONObject("parent");
-            if (!startParent.isEmpty()) {
+
+            if (ObjectUtil.isNotNull(startParent) && !startParent.isEmpty()) {
                 startParent.put(wallId, "start");
             } else {
                 startParent = new JSONObject();