本来运行出来没有错误，正常打开页面，但是一点 市 就报错了，也没有显示值
2021-03-29 23:03:58.789 ERROR 9916 — [nio-8080-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause

java.lang.NullPointerException: null
at com.imocc.xunwuproject.web.controller.house.HouseController.getSupportCities(HouseController.java:21) ~[classes/:na]