SpringMVC service() doget()报空指针 求助

java.lang.NullPointerException
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:889)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)

======================代码===============
@RestController
@RequestMapping("/practiceManager")
public class PracticeManagerController {

private static Logger logger = Logger.getLogger(PracticeManagerController.class);
@Autowired
IPracticeService practiceService;

@RequestMapping(value = "/{id}", method = RequestMethod.GET)
public Response listQuestion(@PathVariable("id") String id) {

    Practice p = null;
    try {
        p = practiceService.getPracticeById(id);
    } catch (Exception e) {
        e.printStackTrace();
    }

    if (null == p) {
       // System.out.println("Question with id " + id + " not found");
        return new Response(HttpStatus.NO_CONTENT, "Question with id " + id + " not found", "");
    }

    return new Response(HttpStatus.OK, "", p);
}

}

javax.servlet.http.HttpServlet.servic 没有servlet 这个包。