总结下就是:
如果消息没有到exchange,则confirm回调,ack=false
如果消息到达exchange,则confirm回调,ack=true
exchange到queue成功,则不回调return
exchange到queue失败,则回调return(需设置mandatory=true,否则不回回调,消息就丢了)
理解Confirm消息确认机制：
消息的确认，是指生产者投递消息后，如果Broker收到消息，则会给我们生产这一个应答。
生产者进行接收应答，用来确定这条消息是否正常的发送到Broker，这种方式也是消息的可靠性投递的核心保障。
如何实现Confirm确认消息？
第一步：在channel上开启确认模式：channel.confirmSelect()
第二步：在channel上添加监听：addConfirmListener，监听成功和失败的返回结果，
根据具体的结果对消息进行重新发送、或者记录日志等后续处理。
1 //生产端代码
2 //1 创建ConnectionFactory
3 ConnectionFactory connectionFactory = new ConnectionFactory();
4 connectionFactory.setHost("127.0.0.1");
5 connectionFactory.setPort(5672);
6 connectionFactory.setVirtualHost("/");
7
8 //2 获取C onnection
9 Connection connection = connectionFactory.newConnection();
10
11 //3 通过Connection创建一个新的Channel
12 Channel channel = connection.createChannel();
13
14
15 //4 指定我们的消息投递模式: 消息的确认模式
16 channel.confirmSelect();
17
18 String exchangeName = "test_confirm_exchange";
19 String routingKey = "confirm.save";
20
21 //5 发送一条消息
22 String msg = "Hello RabbitMQ Send confirm message!";
23 channel.basicPublish(exchangeName, routingKey, null, msg.getBytes());
24
25 //6 添加一个确认监听
26 channel.addConfirmListener(new ConfirmListener() {
27 @Override
28 public void handleNack(long deliveryTag, boolean multiple) throws IOException {
29 System.err.println("-------no ack!-----------");
30 }
31
32 @Override
33 public void handleAck(long deliveryTag, boolean multiple) throws IOException {
34 System.err.println("-------ack!-----------");
35 }
36 });
1 //消费端代码
2 //1 创建ConnectionFactory
3 ConnectionFactory connectionFactory = new ConnectionFactory();
4 connectionFactory.setHost("127.0.0.1");
5 connectionFactory.setPort(5672);
6 connectionFactory.setVirtualHost("/");
7
8 //2 获取C onnection
9 Connection connection = connectionFactory.newConnection();
10
11 //3 通过Connection创建一个新的Channel
12 Channel channel = connection.createChannel();
13
14 String exchangeName = "test_confirm_exchange";
15 String routingKey = "confirm.#";
16 String queueName = "test_confirm_queue";
17
18 //4 声明交换机和队列 然后进行绑定设置, 最后制定路由Key
19 channel.exchangeDeclare(exchangeName, "topic", true);
20 channel.queueDeclare(queueName, true, false, false, null);
21 channel.queueBind(queueName, exchangeName, routingKey);
22
23 //5 创建消费者
24 QueueingConsumer queueingConsumer = new QueueingConsumer(channel);
25 channel.basicConsume(queueName, true, queueingConsumer);
26
27 while(true){
28 Delivery delivery = queueingConsumer.nextDelivery();
29 String msg = new String(delivery.getBody());
30
31 System.err.println("消费端: " + msg);
32 }
Return消息机制
Return Listener用于处理一些不可路由的消息。
我们的消息生产者，通过指定一个Exchange和Routingkey，把消息送到某一个队列中，
然后我们的消费者监听队列，进行消息处理操作。
但是在某些情况下，如果我们在发送消息的时候，当前的exchange不存在或者指定的路由key路由不到，
这个时候我们需要监听这种不可达的消息，就要使用return listener。
在基础API中有一个关键的配置项：
Mandatory：如果为true，则监听会接收到路由不可达的消息，然后进行后续处理，
如果为false，那么broker端自动删除该消息。（默认false）
1 //生产端代码
2 ConnectionFactory connectionFactory = new ConnectionFactory();
3 connectionFactory.setHost("127.0.0.1");
4 connectionFactory.setPort(5672);
5 connectionFactory.setVirtualHost("/");
6
7 Connection connection = connectionFactory.newConnection();
8 Channel channel = connection.createChannel();
9
10 String exchange = "test_return_exchange";
11 String routingKey = "return.save";
12 String routingKeyError = "abc.save";
13
14 String msg = "Hello RabbitMQ Return Message";
15
16
17 channel.addReturnListener(new ReturnListener() {
18 @Override
19 public void handleReturn(int replyCode, String replyText, String exchange,
20 String routingKey, AMQP.BasicProperties properties, byte[] body) throws IOException {
21
22 System.err.println("---------handle return----------");
23 System.err.println("replyCode: " + replyCode);
24 System.err.println("replyText: " + replyText);
25 System.err.println("exchange: " + exchange);
26 System.err.println("routingKey: " + routingKey);
27 System.err.println("properties: " + properties);
28 System.err.println("body: " + new String(body));
29 }
30 });
31
32
33 channel.basicPublish(exchange, routingKeyError, true, null, msg.getBytes());
34
//消费端代码
ConnectionFactory connectionFactory = new ConnectionFactory();
connectionFactory.setHost("127.0.0.1");
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("消费者: " + msg);
}
运行结果：
