上篇《RabbitMQ入门-Routing直连模式》我们介绍了可以定向发送消息,并可以根据自定义规则派发消息。看起来,这个Routing模式已经算灵活的了,但是,这还不够,我们还有更加多样灵活的Topic模式。
/**
* Created by jackie on 17/8/7.
*/
public class EmitLogDirect {
private static final String EXCHANGE_NAME = "direct_logs";
public static void main(String[] argv) throws Exception {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("192.168.3.161");
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.DIRECT);
String severity = getSeverity(argv);
String message = getMessage(argv);
channel.basicPublish(EXCHANGE_NAME, severity, null, message.getBytes("UTF-8"));
System.out.println(" [x] Sent '" + severity + "':'" + message + "'");
channel.close();
connection.close();
}
private static String getSeverity(String[] strings){
if (strings.length < 1)
return "info";
return strings[0];
}
private static String getMessage(String[] strings){
if (strings.length < 2)
return "Hello World!";
return joinStrings(strings, " ", 1);
}
private static String joinStrings(String[] strings, String delimiter, int startIndex) {
int length = strings.length;
if (length == 0 ) return "";
if (length < startIndex ) return "";
StringBuilder words = new StringBuilder(strings[startIndex]);
for (int i = startIndex + 1; i < length; i++) {
words.append(delimiter).append(strings[i]);
}
return words.toString();
}
}
这时候我们给Program argument赋值如下,并启动发送端程序
程序运行完,可以在RabbitMQ管理应用中看到名为“topic_logs”的Exchange。
接收端
/**
* Created by jackie on 17/8/7.
*/
public class ReceiveLogsDirect {
private static final String EXCHANGE_NAME = "direct_logs";
public static void main(String[] argv) throws Exception {
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("192.168.3.161");
Connection connection = factory.newConnection();
Channel channel = connection.createChannel();
channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.DIRECT);
String queueName = channel.queueDeclare().getQueue();
if (argv.length < 1){
System.err.println("Usage: ReceiveLogsDirect [info] [warning] [error]");
System.exit(1);
}
for(String severity : argv){
channel.queueBind(queueName, EXCHANGE_NAME, severity);
}
System.out.println(" [*] Waiting for messages. To exit press CTRL+C");
Consumer consumer = new DefaultConsumer(channel) {
@Override
public void handleDelivery(String consumerTag, Envelope envelope,
AMQP.BasicProperties properties, byte[] body) throws IOException {
String message = new String(body, "UTF-8");
System.out.println(" [x] Received '" + envelope.getRoutingKey() + "':'" + message + "'");
}
};
channel.basicConsume(queueName, true, consumer);
}
}
我们将启动两个消费者,并分别制定两套Routing key的规则。 第一个消费者
第二个消费者
启动两个消费者后,使用发送端发送一条消息,我们可以发现两个消费者都通过Routing key规则派发到了消息
注意:实际上如果Routing key写成了“#”表示能够接受所有的消息,类似广播模式。 这就是Topic模式,到此为止,几大主要RabbitMQ模式已经讲完了。你是否对于RabbitMQ有了一个基本的了解了?