@Component内の@Autowiredサービスがnullポインタ例外を返します。

Question

コンポーネント内でAutowiredされているサービスを使用しようとすると、私のSpring Web Appはjava.lang.NullPointerExceptionを返します。

私は既に@componentを使用しているので、hereのソリューションを試しましたが、それは私のためには機能しませんでした。ここで

は私の完全な例外です：

java.lang.NullPointerException 
    at ir.yasharne.rpi.websocket.MyStompSessionHandler.handleFrame(MyStompSessionHandler.java:81) 
    at org.springframework.messaging.simp.stomp.DefaultStompSession.invokeHandler(DefaultStompSession.java:448) 
    at org.springframework.messaging.simp.stomp.DefaultStompSession.handleMessage(DefaultStompSession.java:399) 
    at org.springframework.web.socket.messaging.WebSocketStompClient$WebSocketTcpConnectionHandlerAdapter.handleMessage(WebSocketStompClient.java:342) 
    at org.springframework.web.socket.sockjs.client.AbstractClientSockJsSession.handleMessageFrame(AbstractClientSockJsSession.java:271) 
    at org.springframework.web.socket.sockjs.client.AbstractClientSockJsSession.handleFrame(AbstractClientSockJsSession.java:213) 
    at org.springframework.web.socket.sockjs.client.WebSocketTransport$ClientSockJsWebSocketHandler.handleTextMessage(WebSocketTransport.java:162) 
    at org.springframework.web.socket.handler.AbstractWebSocketHandler.handleMessage(AbstractWebSocketHandler.java:43) 
    at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter.handleTextMessage(StandardWebSocketHandlerAdapter.java:110) 
    at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter.access$000(StandardWebSocketHandlerAdapter.java:42) 
    at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter$3.onMessage(StandardWebSocketHandlerAdapter.java:81) 
    at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter$3.onMessage(StandardWebSocketHandlerAdapter.java:78) 
    at org.apache.tomcat.websocket.WsFrameBase.sendMessageText(WsFrameBase.java:395) 
    at org.apache.tomcat.websocket.WsFrameBase.processDataText(WsFrameBase.java:495) 
    at org.apache.tomcat.websocket.WsFrameBase.processData(WsFrameBase.java:294) 
    at org.apache.tomcat.websocket.WsFrameBase.processInputBuffer(WsFrameBase.java:133) 
    at org.apache.tomcat.websocket.WsFrameClient.processSocketRead(WsFrameClient.java:95) 
    at org.apache.tomcat.websocket.WsFrameClient.resumeProcessing(WsFrameClient.java:209) 
    at org.apache.tomcat.websocket.WsFrameClient.access$300(WsFrameClient.java:31) 
    at org.apache.tomcat.websocket.WsFrameClient$WsFrameClientCompletionHandler.doResumeProcessing(WsFrameClient.java:186) 
    at org.apache.tomcat.websocket.WsFrameClient$WsFrameClientCompletionHandler.completed(WsFrameClient.java:163) 
    at org.apache.tomcat.websocket.WsFrameClient$WsFrameClientCompletionHandler.completed(WsFrameClient.java:148) 
    at sun.nio.ch.Invoker.invokeUnchecked(Invoker.java:126) 
    at sun.nio.ch.Invoker$2.run(Invoker.java:218) 
    at sun.nio.ch.AsynchronousChannelGroupImpl$1.run(AsynchronousChannelGroupImpl.java:112) 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) 
    at java.lang.Thread.run(Thread.java:745) 

ライン81はMyStompSessionHandler.javaでmoduleService.saveModule(module);です：

@Component 
public class MyStompSessionHandler extends StompSessionHandlerAdapter { 

    @Autowired 
    private ModuleService moduleService; 

    @Override 
    public void afterConnected(StompSession session, StompHeaders connectedHeaders) { 
     session.subscribe("/topic/messages", this); 
    } 

    @Override 
    public Type getPayloadType(StompHeaders headers) { 
     return ServerMessage.class; 
    } 

    @Override 
    public void handleFrame(StompHeaders headers, Object payload) { 
     ServerMessage message = (ServerMessage) payload; 
     if (message.getTopic().equals("newModule")){ 
      ObjectMapper mapper = new ObjectMapper(); 
      try { 
       Map<String, Object> readValue = mapper.readValue(message.getMessage(), Map.class); 
       int id = (int) readValue.get("id"); 
       boolean programmable = (boolean) readValue.get("programmable"); 
       float value = Float.parseFloat(readValue.get("value").toString()); 
       Module module = new Module(); 
       module.setId(id); 
       module.setProgrammable(programmable); 
       module.setValue(value); 
       moduleService.saveModule(module); 
      } catch (IOException e) { 
       System.out.println("HandlerFrame: "); 
       e.printStackTrace(); 
      } 
     } 
    } 

    @Override 
    public void handleException(StompSession session, StompCommand command, StompHeaders headers, byte[] payload, Throwable exception) { 
     exception.printStackTrace(); 
    } 
} 

と私のWebAppConfiguration.java：

@Configuration 
@EnableWebMvc 
@ComponentScan(basePackages = "ir.yasharne.rpi") 
public class WebAppConfiguration extends WebMvcConfigurerAdapter { 

    @Bean 
    public ViewResolver viewResolver() { 
     InternalResourceViewResolver viewResolver = new InternalResourceViewResolver(); 
     viewResolver.setViewClass(JstlView.class); 
     viewResolver.setPrefix("/WEB-INF/views/"); 
     viewResolver.setSuffix(".jsp"); 
     return viewResolver; 
    } 

    @Override 
    public void addResourceHandlers(ResourceHandlerRegistry registery){ 
     registery.addResourceHandler("/static/**").addResourceLocations("/static/"); 
    } 
} 

ModuleServiceImpl.java：

@Service("moduleService") 
@Transactional 
public class ModuleServiceImpl implements ModuleService { 

    @Autowired 
    private ModuleDao moduleDao; 

    @Override 
    public void saveModule(Module module) { 
     moduleDao.saveModule(module); 
    } 
} 

どうすれば修正できますか？

ところで、私はAutowireとコントローラの内部でmoduleServiceを使用しても問題ありません

Answer 1

MyStompSessionHandlerのパッケージは何でそれを使うことができますか？私はそれがir.yasharne.rpiの下でカバーされていないと推測しています。そのパッケージ（ir.yasharne.rpi）の下でそれを動かしてみるか、私はMyStompSessionHandlerは、「コンポーネントスキャン」パス上にないとその中のautowired依存関係が選ばれていない理由です推測している@ComponentScan(basePackages = "ir.yasharne.rpi")

@ComponentScan(basePackages = {"ir.yasharne.rpi", "package.of.MyStompSessionHandler"})に更新します。