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RocketMQ-延时消息

给消息设置延时时间，到一定时间，消费者才能消费的到，中间件内部通过每秒钟扫描，判断是否到达要求时间
现在RocketMq并不支持任意时间的延时，需要设置几个固定的延时等级，从1s到2h分别对应着等级1到18"1s 5s 10s 30s 1m 2m 3m 4m 5m 6m 7m 8m 9m 10m 20m 30m 1h 2h";

但这是默认的，我们可以修改


想修改可以去rocketmq的conf文件夹，修改broker.conf配置参数
该时间是指消息在中间件里面存储的时间

实现延时消息

消费者类：

public class Consumer {public static void main(String[] args) throws Exception {//定义消息消费者(在同一个JVM中,消费者的组名不能重复)DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("helloConsumerGroup");//设置nameServer地址consumer.setNamesrvAddr("43.143.161.59:9876");//设置订阅的主题consumer.subscribe("helloTopic","*");//设置消息的监听器consumer.setMessageListener(new MessageListenerConcurrently() {@Overridepublic ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> list, ConsumeConcurrentlyContext consumeConcurrentlyContext) {for(MessageExt msg:list){String s = new String(msg.getBody(), Charset.defaultCharset());System.out.println("消息消费时间:"+new Date()+",消息的内容:"+s);}return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;}});//启动消费者consumer.start();}
}

生产者类:

public class Producer {public static void main(String[] args) throws Exception {//定义一个生产者对象DefaultMQProducer producer = new DefaultMQProducer("helloGroup");//连接nameServerproducer.setNamesrvAddr("43.143.161.59:9876");//启动生产者producer.start();//设置消息发送的目的地String topic = "helloTopic";//发送消息Message msg = new Message(topic,("延时消息,发送时间:"+new Date()).getBytes(Charset.defaultCharset()));//设置消息延时级别msg.setDelayTimeLevel(3);producer.sendOneway(msg);System.out.println("消息发送完毕.");TimeUnit.SECONDS.sleep(5);//关闭资源producer.shutdown();}
}

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RocketMQ-消息过滤

Tag标签过滤

用Tag方式进行过滤的方法是传入感兴趣的Tag标签，Tag标签是一个普通字符串，是在创建Message的时候添加的，一个Message只能有一个Tag。使用Tag方式过滤非常高效。

生产者类：

public class Producer {public static void main(String[] args) throws Exception {DefaultMQProducer producer = new DefaultMQProducer("tagProduceGroup");producer.setNamesrvAddr("43.143.161.59:9876");producer.start();String topic = "tagFilterTopic";Message msg1 = new Message(topic,"TagA",("消息A").getBytes(Charset.defaultCharset()));Message msg2 = new Message(topic,"TagB",("消息B").getBytes(Charset.defaultCharset()));Message msg3 = new Message(topic,"TagC",("消息C").getBytes(Charset.defaultCharset()));producer.sendOneway(msg1);producer.sendOneway(msg2);producer.sendOneway(msg3);System.out.println("消息发送完毕.");TimeUnit.SECONDS.sleep(5);producer.shutdown();}
}

消费者类：

public class Consumer {public static void main(String[] args) throws Exception {DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("tagFilterConsumerGroup");consumer.setNamesrvAddr("43.143.161.59:9876");consumer.subscribe("tagFilterTopic","TagA || TagC");consumer.setMessageListener(new MessageListenerConcurrently() {@Overridepublic ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> list, ConsumeConcurrentlyContext consumeConcurrentlyContext) {for(MessageExt msg:list){String s = new String(msg.getBody(), Charset.defaultCharset());System.out.println("消息的内容:"+s);}return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;}});//启动消费者consumer.start();}
}

运行结果

SQL标签过滤

可以过滤内容，像写where一样

生产者类：

public class Producer {public static void main(String[] args) throws Exception {DefaultMQProducer producer = new DefaultMQProducer("sqlProduceGroup");producer.setNamesrvAddr("43.143.161.59:9876");producer.start();String topic = "sqlFilterTopic";Message msg1 = new Message(topic,("美女A,年龄22,体重45").getBytes(Charset.defaultCharset()));msg1.putUserProperty("age","22");msg1.putUserProperty("weight","45");Message msg2 = new Message(topic,("美女B,年龄25,体重60").getBytes(Charset.defaultCharset()));msg2.putUserProperty("age","25");msg2.putUserProperty("weight","60");Message msg3 = new Message(topic,("美女C,年龄40,体重70").getBytes(Charset.defaultCharset()));msg3.putUserProperty("age","40");msg3.putUserProperty("weight","70");producer.sendOneway(msg1);producer.sendOneway(msg2);producer.sendOneway(msg3);System.out.println("消息发送完毕.");TimeUnit.SECONDS.sleep(5);producer.shutdown();}
}

消费者类:

public class Consumer {public static void main(String[] args) throws Exception {DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("sqlFilterConsumerGroup");consumer.setNamesrvAddr("43.143.161.59:9876");consumer.subscribe("sqlFilterTopic", MessageSelector.bySql("age>23 and weight>60"));consumer.setMessageListener(new MessageListenerConcurrently() {@Overridepublic ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> list, ConsumeConcurrentlyContext consumeConcurrentlyContext) {for(MessageExt msg:list){String s = new String(msg.getBody(), Charset.defaultCharset());System.out.println("消息的内容:"+s);}return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;}});//启动消费者consumer.start();}
}

运行结果:

原因是因为默认是不支持sql过滤的，需要更改配置文件之后重启broker服务

在文件最后一行添加enablePropertyFilter=true即可
随后重新启动broker服务

之后运行结果

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管控台搜索问题

为什么有时候管控台的消息都没有显示收到此消息，但消费者却能消费?

因为时间问题，因为我们的rocketmq是部署在虚拟机上的，当我们虚拟机和windows时间是同步的时候，消息是没有问题的，控制台显示时间内上下波动一小时的消息，但当虚拟机关掉的时候，时间是不动的，windows的时间却因为电脑里面的一个物理小电池，时间还在正常运行，两者时间不同步了，造成我们发消息是虚拟机的时间，控制台显示的是windows的时间,但消费因为并没有按照时间过滤，所以还是可以接收的到,把时间改一下又可以看到消息了