七、curator recipes之阻塞队列SimpleDistributedQueue
简介
Java在单机环境实现了BlockQueue阻塞队列,与之类似的curator实现了分布式场景下的阻塞队列,SimpleDistributedQueue
官方文档:http://curator.apache.org/curator-recipes/simple-distributed-queue.html
注意:zookeeper虽然可以实现队列,但是官方并不推荐使用zookeeper来做队列,主要原因在于zookeeper的空间大小设计的比较小,且对于大量数据的处理性能比较低,所以比较适合用户处理一些元数据以及应用协调,对于大量数据的建议使用其它分布式队列,比如redisson之类的,或者采用共享存储来实现。
代码示例
import org.apache.curator.framework.CuratorFramework; import org.apache.curator.framework.CuratorFrameworkFactory; import org.apache.curator.framework.recipes.queue.SimpleDistributedQueue; import org.apache.curator.retry.ExponentialBackoffRetry; public class SimpleQueueDemo { private static CuratorFramework client = CuratorFrameworkFactory.newClient("localhost:2181", new ExponentialBackoffRetry(3000, 2)); private static String path = "/queue/path001"; public static void main(String[] args) throws InterruptedException { client.start(); System.out.println("started"); SimpleDistributedQueue queue = new SimpleDistributedQueue(client, path); new Thread(() -> { try { System.out.println("sleeping"); Thread.sleep(3000); System.out.println("sleep end"); new SimpleDistributedQueue(client, path).offer("lay".getBytes("utf-8")); System.out.println("offered"); } catch (Exception e) { System.out.println("exception"); e.printStackTrace(); } }).start(); System.out.println("polling"); String data = null; try { data = new String(queue.take()); } catch (Exception e) { e.printStackTrace(); } System.out.println("data=" + data); client.close(); } }
输出结果
started
polling
sleeping
sleep end
offered
data=lay
主线程会阻塞直到offer了数据