.NullPointerException] with root cause

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause

可能是注入时忘记加入

@Autowired或者@Resource

nested exception is java.lang.NullPointerException] with root cause
空指针异常，对象为空导致的。