Request processing failed; nested exception is java.lang.NullPointerException] with root cause

出现错误：

SEVERE: Servlet.service() for servlet [dispatcher] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root causeroot cause   java.lang.NullPointerException   com.ulotrix.spring.service.PersonServiceImpl.listPersons(PersonServiceImpl.java:35)     com.ulotrix.spring.controller.PersonController.listPersons(PersonController.java:28)         sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

根本原因是引入的Service没有加@Autowired

@Autowired
private GetAppHighUrlByItimeService getAppHighUrlByItimeService;