技術標籤：Zookeeperzookeeperzk非同步方法使用zk非同步方法示例AsyncCallback

程式碼示例

package learn.zk.base;

import org.apache.zookeeper.AsyncCallback;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;

import java.util.List;
import java.util.concurrent.CountDownLatch;

/**
 * @PackageName : learn.zk.base
 * @ClassName : Zk_GetChildren_API_ASync
 * @Author : LingYi
 * @Date : 2021/1/26 20:32
 * @Description : 使用非同步API獲取子節點列表
 */
public class Zk_GetChildren_API_ASync implements Watcher {
    /**
     * zookeeper地址
     */
    static final String CONNECT_ADDR = "192.168.31.207:2181,192.168.31.244:2181,192.168.31.212:2181";
    /**
     * session超時時間
     */
    static final int SESSION_OUT_TIME = 4000;//ms
    /**
     * 訊號量，阻塞程式執行，用於等待zookeeper連線成功，傳送成功訊號
     */
    static final CountDownLatch connectedSemaphore = new CountDownLatch(1);

    public static void main(String[] args) throws Exception {
        ZooKeeper zk = new ZooKeeper(CONNECT_ADDR, SESSION_OUT_TIME, new Zk_GetChildren_API_ASync());
        connectedSemaphore.await();
        System.out.println("......");

        /**
         * path: 路徑
         * watch：是否註冊watch
         * ZkChildrenASync：回撥方法
         * Object：傳遞一個上下文
         **/
        zk.getChildren("/", true, new ZkChildrenASync(), "Context");

        zk.close();
    }

    @Override
    public void process(WatchedEvent event) {
        if (Event.KeeperState.SyncConnected == event.getState() && Event.EventType.None == event.getType()) {
            //如果建立連線成功，則傳送訊號量，讓後續阻塞程式向下執行
            connectedSemaphore.countDown();
            System.out.println("zk 建立連線");
        }
    }
}


/**
 * @PackageName : learn.zk.base
 * @ClassName : ZkChildrenASync
 * @Description : 非同步回撥
 */
class ZkChildrenASync implements AsyncCallback.Children2Callback {

    @Override
    public void processResult(int rc, String path, Object ctx, List<String> children, Stat stat) {
        System.out.println("rc:" + rc + ",path：" + path + "，ctx：" + ctx.toString() + ",children:" + children + ",stat:" + stat);
    }
}
 

執行結果：