lettuce利用stream实现消息推送

1、消息推送

/**
 * @Auther: pshdhx
 * @Date: 2023/02/22/10:38
 * @Description: 往同一个stream队列里边塞值,同一队列的所有消费者组,都会收到消息
 * 模拟 消息推送到服务器
 */
public class TestPubStream {
    public static void main(String[] args) {
        // 创建 Redis 连接
        RedisURI redisURI = RedisURI.Builder.redis("xxxxxx", 6379).build();
        redisURI.setPassword("xxxxxx?");
        RedisClient redisClient = RedisClient.create(redisURI);
        StatefulRedisConnection connection = redisClient.connect();
        try {
            // 获取同步命令对象
            RedisCommands syncCommands = connection.sync();
            // 创建消费者组
            String streamKey = "mystream"; // Stream名称
            String groupName = "myConsumer"; // 消费者组名称
            //检查 groupName 是否存在
            boolean groupExists = false;
            List result = syncCommands.xinfoGroups(streamKey);
            for (Object obj : result) {
                ArrayList objList = (java.util.ArrayList) obj;
                if((objList.get(1)+"").equals(groupName)){
                    groupExists = true;
                    break;
                }
            }

            System.out.println("groupExists = " + groupExists);

            // 如果 groupName 不存在,则创建
            if (!groupExists) {
                syncCommands.xgroupCreate(XReadArgs.StreamOffset.from(streamKey, "0-0"), groupName, XGroupCreateArgs.Builder.mkstream());
            }
            // 发布消息
            syncCommands.xadd(streamKey, "key1", "val1");

        } finally {
            // 关闭连接
            connection.close();
            redisClient.shutdown();
        }
    }
}

2、实现消息订阅

/**
 * @Auther: pshdhx
 * @Date: 2023/02/22/10:40
 * @Description: 模拟 tomcat1 使用消费者组1,消费者1向redis 服务器 订阅推送的消息
 */

public class TestSub1_tomcat1 {
    public static void main(String[] args) {
        // 创建 Redis 连接
        RedisURI redisURI = RedisURI.Builder.redis("xxxxxx", 6379).build();
        redisURI.setPassword("xxxxxxxxxx");
        RedisClient redisClient = RedisClient.create(redisURI);
        StatefulRedisConnection connection = redisClient.connect();
        try {
          

            // 从消费者组中获取消息
            String consumerName = "tomcat1_consumer_name"; // 消费者名称
            RedisCommands streamCommands = connection.sync();

            while (true) {
                List> messages = streamCommands.xreadgroup(
                        Consumer.from(groupName, consumerName),
                        XReadArgs.Builder.block(Duration.ofSeconds(5)), // 阻塞5秒钟等待新消息
                        XReadArgs.StreamOffset.lastConsumed(streamKey)
                );

                if (messages.isEmpty()) {
                    continue; // 在没有新消息时继续轮询
                }

                for (StreamMessage message : messages) {
                    System.out.println("tomcat 1 Received message: " + message.getBody());

                    // 手动确认消息已被处理
                    syncCommands.xack(streamKey, groupName, message.getId());
                }
            }

        } finally {
            // 关闭连接
            connection.close();
            redisClient.shutdown();
        }
    }
}

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