需要模擬一個同步接收消息的MQ消費者:
場景如下:有2個APP,叫APP1 , APP2和APP3
- APP1給APP2發送了一個請求,APP2再去請求APP3,計算由APP3完成,APP2我們沒法改變,但可以改變APP3
- APP1要同步等待APP2的結果返回,可以HTTP輪詢,但太耗資源,所以想到MQ
- APP3計算完了發送一個MQ消息
- APP1接收到MQ消息
- 繼續後面的操作
要實現APP1如何同步等待APP3的消息。
環境
ActiveMQ: 5.15.9
JDK: 1.8
實現
@Test
public void testMQ() throws Exception {
log.info("開始...");
final ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory(
"user", "password", "tcp://host:61616");
final Connection connection = factory.createConnection();
connection.start();
final Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
log.info("Session 創建完");
receiveFromQueue(session, "jimo-q1");
// 第二個queue
receiveFromQueue(session, "jimo-q2");
log.info("結束");
connection.close();
}
private void receiveFromQueue(Session session, String queueName) throws JMSException {
final Queue queue = session.createQueue(queueName);
final MessageConsumer consumer = session.createConsumer(queue);
/*consumer.setMessageListener((m) -> {
try {
System.out.println(((TextMessage) m).getText());
} catch (JMSException e) {
e.printStackTrace();
}
});*/
// 同步等待一條消息,最多等待10分鐘
final Message msg = consumer.receive(10 * 60 * 1000L);
System.out.println(queueName + ":" + ((TextMessage) msg).getText());
}
驗證
在activemq的命令行執行生產消息命令:
./activemq producer --user user --password password --destination queue://jimo-q1 --brokerUrl tcp://host:61616 --messageCount 1
./activemq producer --user user --password password --destination queue://jimo-q2 --brokerUrl tcp://host:61616 --messageCount 1
可看到日誌輸出了
2020 三月 03 09:06:42,731 [main] [INFO] [ServiceTest]: ServiceTest.testMQ( ServiceTest.java:48) - 開始...
2020 三月 03 09:06:43,157 [main] [INFO] [ServiceTest]: ServiceTest.testMQ( ServiceTest.java:54) - Session 創建完
jimo-q1:test message: 0
jimo-q2:test message: 0
2020 三月 03 09:06:55,865 [main] [INFO] [ServiceTest]: ServiceTest.testMQ( ServiceTest.java:60) - 結束