1.交换机（Exchanges ）

生产者生产的消息从不会直接发送到队列，只能将消息发送到交换机，消息能路由发送到队列中其实是由 routingKey(bindingkey)绑定 key 指定的，借由交换机来应对更多种对消息处理的情形，常用的交换机类型有如下几种

名称 类型
直接（发布订阅模式） direct
主题 topic
标题 headers
扇出（路由模式） fanout

2.临时队列

随机名称的队列，一旦断开了消费者的连接，队列将被自动删除

String queueName = channel.queueDeclare().getQueue();

3. fanout exchanges

将接收到的所有消息广播到它知道的所有队列中

消费者1负责向信息打印在控制台上

public class fanout_mod1 {
    private static final String EXCHANGE_NAME = "logs";
    public static void main(String[] argv) throws Exception {
        Channel channel = RabbitMqUtils.getChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
        String queueName = channel.queueDeclare().getQueue();
        //把该临时队列绑定我们的 exchange 其中 routingkey(也称之为 binding key)为空字符串
        channel.queueBind(queueName, EXCHANGE_NAME, "");
        System.out.println("等待接收消息,把接收到的消息打印在屏幕.....");
        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println("控制台打印接收到的消息"+message);
        };
        channel.basicConsume(queueName, true, deliverCallback, consumerTag -> { });
    }
}

消费者2负责将日志保存至本地

public class fanout_mod2 {
    private static final String EXCHANGE_NAME = "logs";
    public static void main(String[] argv) throws Exception {
        Channel channel = RabbitMqUtils.getChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
        String queueName = channel.queueDeclare().getQueue();
        //把该临时队列绑定我们的 exchange 其中 routingkey(也称之为 binding key)为空字符串
        channel.queueBind(queueName, EXCHANGE_NAME, "");
        System.out.println("等待接收消息,把接收到的消息写到文件.....");
        File file = new File("C:\\work\\rabbitmq_info.txt");
        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            FileUtils.writeStringToFile(file,message,"UTF-8");
            System.out.println("数据写入文件成功");
        };
        channel.basicConsume(queueName, true, deliverCallback, consumerTag -> { });
    }
}

生产者发送日志信息

public class EmitLog {
    private static final String EXCHANGE_NAME = "logs";
    public static void main(String[] argv) throws Exception {
        try (Channel channel = RabbitMqUtils.getChannel()) {
            /**
             * 声明一个 exchange
             * 1.exchange 的名称
             * 2.exchange 的类型
             */
            channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
            Scanner sc = new Scanner(System.in);
            System.out.println("请输入信息");
            while (sc.hasNext()) {
                String message = sc.nextLine();
                channel.basicPublish(EXCHANGE_NAME, "", null, message.getBytes("UTF-8"));
                System.out.println("生产者发出消息" + message);
            }
        }
    }
}

4. direct exchange

Fanout 这种交换类型并不能给我们带来很大的灵活性，在这里我们将使用 direct 这种类型来进行替换，这种类型的工作方式是，消息只去到它绑定的routingKey 队列中去

消费者1消费routingkey为error的队列的错误日志，将其保存为日志文件

public class direct_mod1 {
    private static final String EXCHANGE_NAME = "direct_logs";
    public static void main(String[] argv) throws Exception {
        Channel channel = RabbitMqUtils.getChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.DIRECT);
        String queueName = "disk";
        channel.queueDeclare(queueName, false, false, false, null);
        channel.queueBind(queueName, EXCHANGE_NAME, "error");
        System.out.println("等待接收消息.....");
        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            message="接收绑定键:"+delivery.getEnvelope().getRoutingKey()+",消息:"+message;
            File file = new File("C:\\work\\rabbitmq_info.txt");
            FileUtils.writeStringToFile(file,message,"UTF-8");
            System.out.println("错误日志已经接收");
        };
        channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {});
    }
}

消费者2消费routingkey为info,warning的队列的错误日志，将其打印到控制台

public class direct_mod2 {
    private static final String EXCHANGE_NAME = "direct_logs";
    public static void main(String[] argv) throws Exception {
        Channel channel = RabbitMqUtils.getChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.DIRECT);
        String queueName = "console";
        channel.queueDeclare(queueName, false, false, false, null);
        channel.queueBind(queueName, EXCHANGE_NAME, "info");
        channel.queueBind(queueName, EXCHANGE_NAME, "warning");
        System.out.println("等待接收消息.....");
        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" 接收绑定键 :"+delivery.getEnvelope().getRoutingKey()+", 消息:"+message);
        };
        channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {});
    }
}

生产者发送四种routingkey的信息，不存在routingkey为debug的队列，消息丢失

public class direct_emitlog {
    private static final String EXCHANGE_NAME = "direct_logs";
    public static void main(String[] argv) throws Exception {
        try (Channel channel = RabbitMqUtils.getChannel()) {
            channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.DIRECT);
            //创建多个 bindingKey
            Map<String, String> bindingKeyMap = new HashMap<>();
            bindingKeyMap.put("info","普通 info 信息");
            bindingKeyMap.put("warning","警告 warning 信息");
            bindingKeyMap.put("error","错误 error 信息");
            //debug 没有消费这接收这个消息 所有就丢失了
            bindingKeyMap.put("debug","调试 debug 信息");
            for (Map.Entry<String, String> bindingKeyEntry: bindingKeyMap.entrySet()){
                String message = bindingKeyEntry.getValue();
                channel.basicPublish(
                        EXCHANGE_NAME,
                        bindingKeyEntry.getKey(),
                        null,
                        message.getBytes("UTF-8"));
                System.out.println("生产者发出消息:" + message);
            }
        }
    }
}

5. Topics exchange

5.1 Topic的routingkey命名规范

必须是一个单词列表，以点号分隔开。这些单词可以是任意单词，比如说："stock.usd.nyse", "nyse.vmw",

"quick.orange.rabbit".这种类型的。当然这个单词列表最多不能超过 255 个字节。

5.2 匹配规则

*(星号)可以代替一个单词

#(井号)可以替代零个或多个单词

5.3 特点

当一个队列绑定键是#,那么这个队列将接收所有数据，就有点像 fanout了

如果队列绑定键当中没有#和*出现，那么该队列绑定类型就是direct了

5.4 示例

消费者1处理匹配 ​*.orange.*

public class topic_mod1 {
    private static final String EXCHANGE_NAME = "topic_logs";
    public static void main(String[] argv) throws Exception {
        Channel channel = RabbitMqUtils.getChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, "topic");
        //声明 Q1 队列与绑定关系
        String queueName="Q1";
        channel.queueDeclare(queueName, false, false, false, null);
        channel.queueBind(queueName, EXCHANGE_NAME, "*.orange.*");
        System.out.println("等待接收消息.....");
        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" 接收队列 :"+queueName+" 绑定键:"+delivery.getEnvelope().getRoutingKey()+",消息:"+message);
        };
        channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {});
    }
}

消费者2处理匹配​*.*.rabbit和lazy.#

public class topic_mod2 {
    private static final String EXCHANGE_NAME = "topic_logs";
    public static void main(String[] argv) throws Exception {
        Channel channel = RabbitMqUtils.getChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, "topic");
        //声明 Q2 队列与绑定关系
        String queueName="Q2";
        channel.queueDeclare(queueName, false, false, false, null);
        channel.queueBind(queueName, EXCHANGE_NAME, "*.*.rabbit");
        channel.queueBind(queueName, EXCHANGE_NAME, "lazy.#");
        System.out.println("等待接收消息.....");
        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" 接收队列 :"+queueName+" 绑定键:"+delivery.getEnvelope().getRoutingKey()+",消息:"+message);
        };
        channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {
        });
    }
}

生产者

public class topic_emitlog {
    private static final String EXCHANGE_NAME = "topic_logs";
    public static void main(String[] argv) throws Exception {
        try (Channel channel = RabbitMqUtils.getChannel()) {
            channel.exchangeDeclare(EXCHANGE_NAME, "topic");
            /**
             * Q1-->绑定的是
             * 中间带 orange 带 3 个单词的字符串(*.orange.*)
             * Q2-->绑定的是
             * 最后一个单词是 rabbit 的 3 个单词(*.*.rabbit)
             * 第一个单词是 lazy 的多个单词(lazy.#)
             */
            Map<String, String> bindingKeyMap = new HashMap<>();
            bindingKeyMap.put("quick.orange.rabbit","被队列 Q1Q2 接收到");
            bindingKeyMap.put("lazy.orange.elephant","被队列 Q1Q2 接收到");
            bindingKeyMap.put("quick.orange.fox","被队列 Q1 接收到");
            bindingKeyMap.put("lazy.brown.fox","被队列 Q2 接收到");
            bindingKeyMap.put("lazy.pink.rabbit","虽然满足两个绑定但只被队列 Q2 接收一次");
            bindingKeyMap.put("quick.brown.fox","不匹配任何绑定不会被任何队列接收到会被丢弃");
            bindingKeyMap.put("quick.orange.male.rabbit","是四个单词不匹配任何绑定会被丢弃");
            bindingKeyMap.put("lazy.orange.male.rabbit","是四个单词但匹配 Q2");
            for (Map.Entry<String, String> bindingKeyEntry: bindingKeyMap.entrySet()){
                String bindingKey = bindingKeyEntry.getKey();
                String message = bindingKeyEntry.getValue();
                channel.basicPublish(EXCHANGE_NAME,bindingKey, null,
                        message.getBytes("UTF-8"));
                System.out.println("生产者发出消息" + message);
            }
        }
    }
}