rabbitmq_delayed_message_exchange
机制
安装插件后会生成新的Exchange类型x-delayed-message，该类型消息支持延迟投递机制,接收到消息后并未立即将消息投递至目标队列中，而是存储在mnesia(一个分布式数据系统)表中，并且当前节点是磁盘节点，那么节点重启后，消息还能保留。检测消息延迟时间，如达到可投递时间时并将其通过x-delayed-type类型标记的交换机类型投递至目标队列。但是要注意的是，如果集群中只有一个磁盘节点，如果说磁盘节点丢失，或者节点上的插件失效。意味着消息将会丢失。
特性
- 可通过 x-delayed-type 指定类型 为 direct fanout topic 等
- 检测消息延迟时间，如果达到投递时间，通过x-delayed-type 标记的交换机类型进行投递。
- 消息存储在声明交换机的那个节点上，消息发送到延时交换机上，消息还未到发送时间，此时停机该节点，消费者不能消费此延时消息，后启动该节点，消息会被重新投递，消费者能够消费此延时消息。
- 磁盘节点，消息持久化，交换机持久化，消息不会丢失。
延时队列申明
代码语言：javascript复制Map<String,Object> map =new HashMap<>();
map.put("x-delayed-type", "direct");
channel.exchangeDeclare(exchangeName, "x-delayed-message", true, false, map);插件安装
下载
代码语言：javascript复制wget https://dl.bintray.com/rabbitmq/community-plugins/3.6.x/rabbitmq_delayed_message_exchange/rabbitmq_delayed_message_exchange-20171215-3.6.x.zip解压
下载后解压，并将其拷贝至(使用Linux Debian/RPM部署)rabbitmq服务器目录：/usr/local/rabbitmq/plugins中（windows安装目录rabbitmq_server-versionplugins ) /usr/lib/rabbitmq/lib/rabbitmq_server-3.6.12/plugins
代码语言：javascript复制unzip rabbitmq_delayed_message_exchange-20171215-3.6.x.zip启用插件
使用命令rabbitmq-plugins enable rabbitmq_delayed_message_exchang启用插件
rabbitmq-plugins enable rabbitmq_delayed_message_exchang输出结果
代码语言：javascript复制The following plugins have been enabled:
rabbitmq_delayed_message_exchange代码示例
生产者
代码语言：javascript复制import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
public class Producer {
public static void main(String[] args) throws Exception {
ConnectionFactory connectionFactory = new ConnectionFactory();
connectionFactory.setVirtualHost("/");
connectionFactory.setHost("172.31.1.135");
connectionFactory.setUsername("xx");
connectionFactory.setPassword("xx");
connectionFactory.setPort(5672);
Connection connection = connectionFactory.newConnection();
Channel channel = connection.createChannel();
String exchangeName = "delay-exchange";
String routingkey = "delay.delay";
String queueName = "delay_queueName";
//x-delayed-message 声明
Map<String,Object> map =new HashMap<>();
map.put("x-delayed-type", "direct");
channel.exchangeDeclare(exchangeName, "x-delayed-message", true, false, map);
//注意：arguments需要声明在队列上，声明在交换机上是不会起作用的。
channel.queueDeclare(queueName, true, false, false, map);
channel.queueBind(queueName,exchangeName,routingkey);
for (int i = 0; i < 3; i ) {
// deliveryMode=2 持久化，expiration 消息有效时间
String msg = "delayed payload".getBytes("UTF-8") " " new Date().getTime();
byte[] messageBodyBytes = msg.getBytes();
Map<String, Object> headers = new HashMap<String, Object>();
headers.put("x-delay", 50000);
AMQP.BasicProperties.Builder props = new AMQP.BasicProperties.Builder().headers(headers);
channel.basicPublish(exchangeName, routingkey, props.build(), messageBodyBytes);
}
}
}消费者
代码语言：javascript复制import java.io.IOException;
import java.util.Date;
import com.rabbitmq.client.AMQP.BasicProperties;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;
public class Consumer {
public static void main(String[] args) throws Exception {
ConnectionFactory connectionFactory = new ConnectionFactory();
connectionFactory.setVirtualHost("/");
connectionFactory.setHost("172.31.1.135");
connectionFactory.setPort(5672);
connectionFactory.setUsername("xxx");
connectionFactory.setPassword("xxx");
Connection connection = connectionFactory.newConnection();
Channel channel = connection.createChannel();
String queueName = "delay_queueName";
channel.queueDeclare(queueName,true,false,false,null);
channel.basicConsume(queueName, false, "myConsumer Tag", new DefaultConsumer(channel){
@Override
public void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties, byte[] body) throws IOException {
String routingKey = envelope.getRoutingKey();
String convernType = properties.getContentType();
long deliveryTag = envelope.getDeliveryTag();
System.out.println("routingKey:" routingKey ",convernType:" convernType ",deliveryTag:" deliveryTag ",Msg body:" new String(body) " " new Date().getTime());
channel.basicAck(deliveryTag, false);
}
});
}
}
