I am now using java to design the redis pub/sub system and got a problem. I will show you the details:
The publisher here :
public class RedisMessagePublisher implements MessagePublisher {
public RedisMessagePublisher(StringRedisTemplate redisTemplate,ChannelTopic topic)
{
this.redisTemplate = redisTemplate;
this.topic = topic;
}
private StringRedisTemplate redisTemplate;
private ChannelTopic topic;
@Override
public void publish(String message) {
redisTemplate.convertAndSend(topic.getTopic(), message);
}
}
The publisher is correct and can work correctly.
Then let's move to subscriber class:
public class RedisMessageSubscriber implements MessageListener {
//action inspect here
private Action2<Message, byte[]> action;
public void setAction(Action2<Message, byte[]> action) {
logger.info("action set");
this.action = action;
}
private static Logger logger = LogManager.getLogger(RedisMessageSubscriber.class);
@Override
public void onMessage(Message message, byte[] bytes) {
logger.info("===> redis subscribe message in <===");
if (action != null)
action.call(message, bytes);
else
logger.info("===> action is null <===");
}
}
In subscriber class, I used the RxJava to inject the Action so that I can use it much more easily.
But the question is here, after I published the message from publisher, I can c that the message can be transferred to onMessage method, the log print was not what I expected:
===> redis subscribe message in <===
===> action is null <===
What I expected is that when I published a new message, the subscriber got it and ran the Action that I created.
The service I used to trigger the publisher and subscriber below:
@RestController("redispubsubcontroller")
@RequestMapping(value = "/redis")
public class redispubsubcontroller {
@Autowired
private RedisMessagePublisher redisMessagePublisher;
@Autowired
private RedisMessageSubscriber redisMessageSubscriber;
private static Logger logger = LogManager.getLogger(redispubsubcontroller.class);
@RequestMapping(value = "/publisher", method = {RequestMethod.GET})
public ApiResponse getConfig(String message,HttpServletRequest request,
HttpServletResponse response) {
redisMessageSubscriber.setAction(new Action2<Message, byte[]>() {
@Override
public void call(Message message, byte[] bytes) {
ObjectMapper objectMapper = new ObjectMapper();
try {
String result = objectMapper.readValue(message.getBody(), String.class);
logger.info("receive："+result);
} catch (IOException e) {
e.printStackTrace();
}
}
});
redisMessagePublisher.publish(message);
return new ApiResponse("success","message sent");
}
}
From above code, you can c that I subscribed the topic and set a new action to the subscriber:
redisMessageSubscriber.setAction(new Action2<Message, byte[]>() {
@Override
public void call(Message message, byte[] bytes) {
ObjectMapper objectMapper = new ObjectMapper();
try {
String result = objectMapper.readValue(message.getBody(), String.class);
logger.info("receive："+result);
} catch (IOException e) {
e.printStackTrace();
}
}
});
But I don't know why, after triggering the publisher, the subscriber can get the message but hold NULL Action still, the Action I created didn't pass to it.
Anyone can help? Is there any problem with this mechanism?
====EDIT=====
RedisMessageConfig code below:
@Configuration
public class RedisMessageConfig {
@Bean
ChannelTopic topic() {
return new ChannelTopic("useraddresspubsub:queue");
}
@Bean
MessageListenerAdapter messageListener() {
return new MessageListenerAdapter(new RedisMessageSubscriber());
}
@Autowired
private RedisConnectionFactory JedisConnectionFactory;
@Bean
RedisMessageListenerContainer redisContainer() {
final RedisMessageListenerContainer container = new RedisMessageListenerContainer();
container.setConnectionFactory(JedisConnectionFactory);
container.addMessageListener(messageListener(), topic());
return container;
}
}
====Solved====
Finally I got this solved per mp's idea, slightly changed myredismessagesubscriber to myredismessageconfig because the flow is from redismessageconfig to redismessagesubscriber, so in redismessageconfig, I need to first inject the action to it, then redismessageconfig will create new redismessagesubscriber and hold the new created action. The code below:
@Component
public class MyRedisMessageConfig extends RedisMessageConfig {
private static Logger logger =LogManager.getLogger(MyRedisMessageConfig.class);
public MyRedisMessageConfig() {
super.action = new Action2<Message, byte[]>() {
@Override
public void call(Message message, byte[] bytes) {
String result = new String(message.getBody());
logger.info("received：" + result);
}
};
}
}
Screenshot below:
