我正试图在用户的连接建立之后,在websockethandler中使用rabbitmq发送消息。问题是,rabbitmq生产者bean为空。从控制器调用生产者工作得非常好,但是当我尝试从websockethandler bean调用生产者时,如果失败,则出现空指针异常:
websocket配置:
@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
registry.addHandler(new MyWebSocketHandler(), "/connect");
}
}
websocket处理程序bean,其中空指针异常为:
@Component
public class MyWebSocketHandler extends TextWebSocketHandler {
private static final Logger LOG = LoggerFactory.getLogger(WebSocketConfig.class);
@Autowired
QueueProducer producer; //NULL
List<WebSocketSession> sessions = new CopyOnWriteArrayList<>();
@Override
public void afterConnectionEstablished(WebSocketSession session) throws Exception {
sessions.add(session);
List<String> lol = session.getHandshakeHeaders().get("User-Agent");
//Calling the rabbitmq producer
producer.produce("Hi Mark");//NULL
}
rabbitmq配置:
@Configuration
public class RabbitConfiguration {
@Value("${fanout.exchange}")
private String fanoutExchange;
@Value("${queue.name}")
private String queueName;
@Bean
Queue queue() {
return new Queue(queueName, true);
}
@Bean
FanoutExchange exchange() {
return new FanoutExchange(fanoutExchange);
}
@Bean
Binding binding(Queue queue, FanoutExchange exchange) {
return BindingBuilder.bind(queue).to(exchange);
}
}
rabbitmq生产者代码:
@Component
public class QueueProducer {
protected Logger logger = LoggerFactory.getLogger(getClass());
@Value("${fanout.exchange}")
private String fanoutExchange;
private final RabbitTemplate rabbitTemplate;
@Autowired
public QueueProducer(RabbitTemplate rabbitTemplate) {
super();
this.rabbitTemplate = rabbitTemplate;
}
public void produce(String message) throws Exception {
logger.info("Storing notification...");
rabbitTemplate.setExchange(fanoutExchange);
rabbitTemplate.convertAndSend(message);
logger.info("Notification stored in queue sucessfully");
}
}
堆栈跟踪:
java.lang.NullPointerException: null
at com.ta9.common.Config.MyWebSocketHandler.afterConnectionEstablished(MyWebSocketHandler.java:43) ~[classes/:na]
at org.springframework.web.socket.handler.WebSocketHandlerDecorator.afterConnectionEstablished(WebSocketHandlerDecorator.java:70) ~[spring-websocket-5.3.8.jar:5.3.8]
at org.springframework.web.socket.handler.LoggingWebSocketHandlerDecorator.afterConnectionEstablished(LoggingWebSocketHandlerDecorator.java:48) ~[spring-websocket-5.3.8.jar:5.3.8]
at org.springframework.web.socket.handler.ExceptionWebSocketHandlerDecorator.afterConnectionEstablished(ExceptionWebSocketHandlerDecorator.java:48) ~[spring-websocket-5.3.8.jar:5.3.8]
at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter.onOpen(StandardWebSocketHandlerAdapter.java:104) ~[spring-websocket-5.3.8.jar:5.3.8]
at org.apache.tomcat.websocket.server.WsHttpUpgradeHandler.init(WsHttpUpgradeHandler.java:135) ~[tomcat-embed-websocket-9.0.48.jar:9.0.48]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:940) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1723) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.48.jar:9.0.48]
at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
先谢谢你。
1条答案
按热度按时间xytpbqjk1#
这是预期的行为。让我们再一次查看您的代码:
你知道你在做什么吗
new
手动。您不需要依赖于这里的依赖注入容器。你的MyWebSocketHandler
在这种情况下,它不是一个bean。因为它被标记为@Component
我认为它被正确地扫描了,并作为bean提供给应用程序上下文。因此,您可以这样做来解决您的问题: