1 圖解
2 消息如何進入死信隊列
消息過期
隊列長度已滿
消息被拒絕且不再重新嘗試
3 應用場景
在定義業務隊列時,指定一個死信交換機,並綁定一個死信隊列
當消息變成死信時,該消息就會被髮送到該死信隊列上
這樣就方便我們查看消息失敗的原因
4 代碼樣例
4.1 生產者
/**
* 定義死信隊列相關信息
*/
public final static String deadQueueName = "dead_queue";
public final static String deadRoutingKey = "dead_routing_key";
public final static String deadExchangeName = "dead_exchange";
/**
* 死信隊列 交換機標識符
*/
public static final String DEAD_LETTER_QUEUE_KEY = "x-dead-letter-exchange";
/**
* 死信隊列交換機綁定鍵標識符
*/
public static final String DEAD_LETTER_ROUTING_KEY = "x-dead-letter-routing-key";
// 郵件隊列
private String FANOUT_EMAIL_QUEUE = "fanout_queue";
/**
* 配置死信隊列
*
* @return
*/
@Bean
public Queue deadQueue() {
Queue queue = new Queue(deadQueueName, true);
return queue;
}
/*
* 創建死信交換機
*/
@Bean
public DirectExchange deadExchange() {
return new DirectExchange(deadExchangeName);
}
/*
* 將死信隊列與死信交換機綁定
*/
@Bean
public Binding bindingDeadExchange(Queue deadQueue, DirectExchange deadExchange) {
return BindingBuilder.bind(deadQueue).to(deadExchange).with(deadRoutingKey);
}
/**
* 聲明業務隊列,將死信交換機與隊列進行綁定
* @return Queue
*/
@Bean
public Queue fanOutQueue() {
Map<String, Object> args = new HashMap<>(2);
args.put(DEAD_LETTER_QUEUE_KEY, deadExchangeName);
args.put(DEAD_LETTER_ROUTING_KEY, deadRoutingKey);
return new Queue(FANOUT_EMAIL_QUEUE, true, false, false, args);
}
4.2 消費者
try {
// 通知mq服務器刪除該消息
channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
} catch (Exception e) {
// 消息放入死信隊列
channel.basicNack(message.getMessageProperties().getDeliveryTag(), false, false);
}
5 注意事項
如果創建隊列時,未綁定死信交換機,如果想要綁定,需要將隊列刪除,重新創建