Return Listener
Return Listener 通常用於吃力一些不可路由的消息。例如：在某些情況下，在我們發送消息的時候當前指的Exchange不存在或者指定的routing key找不到，這個時候我們需要監聽這種不可達的消息，就可以使用Return Listener。
Mandatory屬性
true: 監聽器會接收到路由不可達的消息，然後進行後續處理；
false：Broker端會自動刪除該不可達的消息；
源碼
public void basicPublish(String exchange, String routingKey, boolean mandatory, BasicProperties props, byte[] body) throws IOException {
this.basicPublish(exchange, routingKey, mandatory, false, props, body);
}
例子
Consumer.java
public class Consumer {
public static void main(String[] args) throws Exception {
ConnectionFactory connectionFactory = new ConnectionFactory();
connectionFactory.setHost("xxx.xxx.xxx.xxx");
connectionFactory.setPort(5672);
connectionFactory.setVirtualHost("/");
Connection connection = connectionFactory.newConnection();
Channel channel = connection.createChannel();
String exchangeName = "test_return_exchange";
String routingKey = "return.#";
String queueName = "test_return_queue";
channel.exchangeDeclare(exchangeName, "topic", true, false, null);
channel.queueDeclare(queueName, true, false, false, null);
channel.queueBind(queueName, exchangeName, routingKey);
QueueingConsumer queueingConsumer = new QueueingConsumer(channel);
channel.basicConsume(queueName, true, queueingConsumer);
while(true){
Delivery delivery = queueingConsumer.nextDelivery();
String msg = new String(delivery.getBody());
System.err.println("消費者: " + msg);
}
}
}
Producer.java
public class Producer {
public static void main(String[] args) throws Exception {
ConnectionFactory connectionFactory = new ConnectionFactory();
connectionFactory.setHost("xxx.xxx.xx.xx");
connectionFactory.setPort(5672);
connectionFactory.setVirtualHost("/");
Connection connection = connectionFactory.newConnection();
Channel channel = connection.createChannel();
String exchange = "test_return_exchange";
String routingKey = "return.save";
String routingKeyError = "abc.save";
String msg = "Hello RabbitMQ Return Message";
channel.addReturnListener(new ReturnListener() {
@Override
public void handleReturn(int replyCode, String replyText, String exchange,
String routingKey, AMQP.BasicProperties properties, byte[] body) throws IOException {
System.err.println("---------handle return----------");
System.err.println("replyCode: " + replyCode);
System.err.println("replyText: " + replyText);
System.err.println("exchange: " + exchange);
System.err.println("routingKey: " + routingKey);
System.err.println("properties: " + properties);
System.err.println("body: " + new String(body));
}
});
channel.basicPublish(exchange, routingKeyError, true, null, msg.getBytes());
}
}