zookeeper基础操作及其常用api

zookeeper基础操作及其常用api

zookeeper

1. zookeeper构造函数参数名称
2. ProcessResult参数说明
3. create参数说明
4. delete参数说明
5. getChild参数说明
6. getdata参数说明
7. setdata参数说明
8. exist参数说明

1.1zookeeper构造函数参数

1.2 Process参数
1.3create参数

1.4Delete参数说明
1.5getChildren参数
1.6getData参数
1.7setData参数
1.8exists参数

zookeeper基础使用代码

import org.apache.zookeeper.*;
import java.io.IOException;
import java.util.concurrent.CountDownLatch;

/**
 * @Auther: cpb
 * @Date: 2019/1/23 09:59
 * @Description:
 */
public class ZookeeperTest {
    /** zookeeper地址 */
    static final String CONNECT_ADDR = "localhost:2181";
    /** session超时时间 */
    static final int SESSION_OUTTIME = 2000;//ms
    /** 信号量，阻塞程序执行，用于等待zookeeper连接成功，发送成功信号 */
    static final CountDownLatch connectedSemaphore = new CountDownLatch(1);
    public static void main(String[] args) {
        Watcher watcher = new Watcher() {
            public void process(WatchedEvent watchedEvent) {
                //获取事件状态
                Event.KeeperState keeperState = watchedEvent.getState();
                //获取事件类型
                Event.EventType eventType = watchedEvent.getType();
                //如果建立连接
                if(Event.KeeperState.SyncConnected == keeperState){
                    if (Event.EventType.None == eventType){
                        //连接成功，发送信号，后面程序阻塞
                        connectedSemaphore.countDown();
                        System.out.println("zookeeper 建立连接");
                    }
                }

            }
        };
        //构造函数参数：地址，session过期时间，watcher回调函数
        try {
            ZooKeeper zooKeeper = new ZooKeeper(CONNECT_ADDR,SESSION_OUTTIME,watcher);
            //进行阻塞，直达watcher监听到连接事件
            connectedSemaphore.await();
            //判断是否存在节点
            if(null == zooKeeper.exists("/myroot",false)) {
                //创建父节点 参数：path，data(byte类型),acl策略（加密策略），节点类型(是否持久化，是否顺序)
                zooKeeper.create("/myroot", "root data".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
            }
            if(null == zooKeeper.exists("/myroot/child",false)) {
                //创建临时子节点（发送异常会自动移除）
                zooKeeper.create("/myroot/child", "child data".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
            }
            //获取节点数据 参数：path(路径),watch（监听器）,stat(各种源数据，事务id，版本号，时间戳，大小)
            String data = new String(zooKeeper.getData("/myroot/child",false,null));
            System.out.println(data);
            System.out.println(zooKeeper.getChildren("/myroot",false));

            //修改节点数据 参数：path，data ，version
            zooKeeper.setData("/myroot/child","你好吗".getBytes(),-1);
            System.out.println(new String(zooKeeper.getData("/myroot/child",false,null)));


            //判断节点是否存在
            System.out.println(zooKeeper.exists("/myroot/child",false));


            //删除节点
            zooKeeper.delete("root/child",-1);
            System.out.println(zooKeeper.exists("/myroot/child",false));

            zooKeeper.close();
        }catch (KeeperException e){
            e.printStackTrace();
        }catch (InterruptedException e) {
            e.printStackTrace();
        }catch (IOException e) {
            e.printStackTrace();
        }
    }
}