Java API操作ZK node

创建会话

• 建立简单连接

/**
 * 测试创建Zk会话
 * Created by liuhuichao on 2017/7/25.
 */
public class ZooKeeper_Constructor_Usage_Simple implements Watcher {
    private static CountDownLatch connectedSemaphore=new CountDownLatch(1);

    public static void main(String[] args) throws Exception{
        ZooKeeper zk=new ZooKeeper("192.168.99.215:2181",5000,new ZooKeeper_Constructor_Usage_Simple());
        System.out.println(zk.getState());
        connectedSemaphore.await();
        System.out.println("zk session established");
    }

    /**
     * 处理来自ZK服务端的watcher通知
     * @param watchedEvent
     */
    @Override
    public void process(WatchedEvent watchedEvent) {
        System.out.println("receive watched event:"+watchedEvent);
        if(Event.KeeperState.SyncConnected==watchedEvent.getState()){
            connectedSemaphore.countDown();//解除等待阻塞
        }
    }
}

• 复用会话

/**
 * 复用sessionId和sessionPassword的会话
 * Created by liuhuichao on 2017/7/25.
 */
public class ZooKeeper_Constructor_Usage_With_sid_password implements Watcher {

    private static CountDownLatch connectedSemaphore=new CountDownLatch(1);
    @Override
    public void process(WatchedEvent watchedEvent) {
        System.out.println("receive watched event:"+watchedEvent);
        if(Event.KeeperState.SyncConnected==watchedEvent.getState()){
            connectedSemaphore.countDown();
        }

    }

    public static void main(String[] args) throws Exception{
        ZooKeeper zooKeeper=new ZooKeeper("lhc-centos0:2181",5000,new ZooKeeper_Constructor_Usage_With_sid_password());
        connectedSemaphore.await();
        long sessionId=zooKeeper.getSessionId();
        byte[] password=zooKeeper.getSessionPasswd();

        /**使用错误的sessionID跟sessionPwd连连接测试[192.168.99.215 lhc-centos0]**/
        ZooKeeper zkWrong=new ZooKeeper("lhc-centos0:2181",5000,new ZooKeeper_Constructor_Usage_With_sid_password(),1l,"lhc".getBytes());
        /**使用正确的来进行连接**/
        ZooKeeper zkTrue=new ZooKeeper("lhc-centos0:2181",5000,new ZooKeeper_Constructor_Usage_With_sid_password(),sessionId,password);
        Thread.sleep(Integer.MAX_VALUE);
    }
}

创建节点

• 使用同步API创建节点

/**
 * 使用同步API创建一个节点
 * Created by liuhuichao on 2017/7/25.
 */
public class ZooKeeper_Create_API_Sync_Usage implements Watcher {
    private static CountDownLatch connectedSemaphore=new CountDownLatch(1);
    @Override
    public void process(WatchedEvent watchedEvent) {
        if(Event.KeeperState.SyncConnected==watchedEvent.getState()){
            connectedSemaphore.countDown();
        }
    }

    public static void main(String[] args) throws Exception{
        ZooKeeper zooKeeper=new ZooKeeper("192.168.99.215:2181",5000,new ZooKeeper_Create_API_Sync_Usage());
        connectedSemaphore.await();
        String path1=zooKeeper.create("/zk-test1","lhc".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);//临时结点
        System.out.println(path1+" 创建成功！");

        String path2=zooKeeper.create("/zk-test2","lllhhhhhhhhhhhhhhhhc".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.EPHEMERAL_SEQUENTIAL);
        System.out.println(path2+"  创建成功！");

    }
}

• 使用异步API创建一个节点

/**
 * 使用异步API创建一个节点
 * Created by liuhuichao on 2017/7/25.
 */
public class ZooKeeper_Create_API_ASync_Usage implements Watcher{
    private static CountDownLatch connectedSamphore=new CountDownLatch(1);

    @Override
    public void process(WatchedEvent watchedEvent) {
        if(watchedEvent.getState()== Event.KeeperState.SyncConnected){
            connectedSamphore.countDown();
        }
    }

    public static void main(String[] args) throws Exception{
        ZooKeeper zk1=new ZooKeeper("lhc-centos0:2181",5000,new ZooKeeper_Create_API_ASync_Usage());
        connectedSamphore.await();
        zk1.create("/zk-test-1","".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT,new IStringCallBack(),"i am a context");
        zk1.create("/zk-test-2","".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT,new IStringCallBack(),"i am a context");
        zk1.create("/zk-test-3","".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT_SEQUENTIAL,new IStringCallBack(),"i am a context");
        Thread.sleep(Integer.MAX_VALUE);
    }
}

/**
 * Created by liuhuichao on 2017/7/26.
 */
public class IStringCallBack implements AsyncCallback.StringCallback{

        @Override
        public void processResult(int rc, String path, Object ctx, String name) {
            System.out.println("result:"+rc+"; path="+path+" ctx="+ctx+" name = "+name);
        }
}

删除节点

/**
 * 删除zk的持久结点
 * Created by liuhuichao on 2017/7/26.
 */
public class ZooKeeperDeleteNode implements Watcher {

    private  static CountDownLatch conntedSamphore=new CountDownLatch(1);
    @Override
    public void process(WatchedEvent watchedEvent) {
        if(Event.KeeperState.SyncConnected==watchedEvent.getState()){
            conntedSamphore.countDown();
        }

    }

    public static void main(String[] args) throws Exception{
        /**同步删除节点**/
        ZooKeeper zooKeeper=new ZooKeeper("lhc-centos0:2181",5000,new ZooKeeperDeleteNode());
        conntedSamphore.await();
        zooKeeper.delete("/zk-test-30000000014",0);
    }

}

读取数据

• 使用同步API获取子节点列表

/**
 *获取结点-同步
 * Created by liuhuichao on 2017/7/26.
 */
public class ZooKeeper_GetChildren_API_Sync_Usage implements Watcher {
    private  static CountDownLatch conntedSamphore=new CountDownLatch(1);
    private static ZooKeeper zooKeeper=null;

    @Override
    public void process(WatchedEvent watchedEvent) {
        if(Event.KeeperState.SyncConnected==watchedEvent.getState()){
            conntedSamphore.countDown();
        }else if(watchedEvent.getType()== Event.EventType.NodeChildrenChanged){
            try {
                System.out.println("--------------------------------------reget children:"+zooKeeper.getChildren(watchedEvent.getPath(),true));
            } catch (KeeperException e) {
                e.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

    }

    public static void main(String[] args) throws Exception{
        String path="/zk-test-1";
        zooKeeper=new ZooKeeper("lhc-centos0:2181",5000,new ZooKeeper_GetChildren_API_Sync_Usage());
        conntedSamphore.await();
        zooKeeper.create(path+"/test1","".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.EPHEMERAL);
        List<String> childrenList=zooKeeper.getChildren(path,true);
        System.out.println(childrenList);
        zooKeeper.create(path+"/test2","".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.EPHEMERAL);
        Thread.sleep(Integer.MAX_VALUE);
    }

}

• 使用异步API获取子节点列表

**
 * 异步获取结点
 * Created by liuhuichao on 2017/7/26.
 */
public class ZooKeeper_GetChildren_API_ASync_Usage implements Watcher {

    private static CountDownLatch connectedSemphore=new CountDownLatch(1);
    private static ZooKeeper zk=null;

    @Override
    public void process(WatchedEvent watchedEvent) {
        if(Event.KeeperState.SyncConnected==watchedEvent.getState()){
            connectedSemphore.countDown();
        }else if(watchedEvent.getType()== Event.EventType.NodeChildrenChanged){
            try {
                System.out.println("node changed===="+zk.getChildren(watchedEvent.getPath(),true));
            } catch (KeeperException e) {
                e.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

    }

    public static void main(String[] args) throws Exception{
        String path="/zk-test-1";
        zk=new ZooKeeper("lhc-centos0:2181",5000,new ZooKeeper_GetChildren_API_ASync_Usage());
        connectedSemphore.await();
        zk.create(path+"/test3","".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
        zk.getChildren(path,true,new ICChild2Callback(),null);
        Thread.sleep(Integer.MAX_VALUE);
    }

}

/**
 * 异步获取结点回调接口
 * Created by liuhuichao on 2017/7/26.
 */
public class ICChild2Callback implements AsyncCallback.Children2Callback{

    @Override
    public void processResult(int rc, String path, Object ctx, List<String> children, Stat stat) {
        System.out.println("get children zonde result:[reponse code:"+rc+" path="+path+" ctx="+ctx+"  childrenlist="+children+" stat="+stat);
    }
}

• 使用同步API获取结点数据

/**
 *
 * 同步获取数据
 * Created by liuhuichao on 2017/7/27.
 */
public class GetData_API_Sync_Usage  implements Watcher{

    private static CountDownLatch conntedSamphore=new CountDownLatch(1);
    private static ZooKeeper zk=null;
    private static Stat stat=new Stat();
    @Override
    public void process(WatchedEvent watchedEvent) {
        if(Event.KeeperState.SyncConnected==watchedEvent.getState()){
            conntedSamphore.countDown();
        }else if(watchedEvent.getType()== Event.EventType.NodeCreated){
            System.out.println("node changed:"+watchedEvent.getPath());
        }

    }

    public static void main(String[] args) throws Exception{
        String path="/test-1";
       zk =new ZooKeeper("rc-zkp-datn-rse-nmg-ooz-woasis:2181",5000,new GetData_API_Sync_Usage());
        conntedSamphore.await();
        System.out.println("zk-19 连接成功！");
        //zk.create(path+"/lhc", "".getBytes(),ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
        List<String> children=zk.getChildren(path,new GetData_API_Sync_Usage());
        System.out.println("children node:"+children);
        zk.setData(path+"/lhc","memeda".getBytes(),-1);
        byte[] nodeValue=zk.getData(path+"/lhc",true,stat);
        System.out.println(new String(nodeValue));

    }
}

• 使用异步API获取结点数据

/**
 *
 * 同步/异步获取数据
 * Created by liuhuichao on 2017/7/27.
 */
public class GetData_API_Sync_Usage  implements Watcher{

    private static CountDownLatch conntedSamphore=new CountDownLatch(1);
    private static ZooKeeper zk=null;
    private static Stat stat=new Stat();
    @Override
    public void process(WatchedEvent watchedEvent) {
        if(Event.KeeperState.SyncConnected==watchedEvent.getState()){
            conntedSamphore.countDown();
        }else if(watchedEvent.getType()== Event.EventType.NodeCreated){
            System.out.println("node changed:"+watchedEvent.getPath());
        }

    }

    public static void main(String[] args) throws Exception{
        String path="/test-1";
       zk =new ZooKeeper("rc-zkp-datn-rse-nmg-ooz-woasis:2181",5000,new GetData_API_Sync_Usage());
        conntedSamphore.await();
        System.out.println("zk-19 连接成功！");
        //zk.create(path+"/lhc", "".getBytes(),ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
        List<String> children=zk.getChildren(path,new GetData_API_Sync_Usage());
        System.out.println("children node:"+children);
        zk.setData(path+"/lhc","lllhc".getBytes(),-1);
        zk.getData(path+"/lhc",true,new IDataCallback(),null);//异步获取数据
        Thread.sleep(Integer.MAX_VALUE);
    }
}

/**
 * 异步获取node数据回调
 * Created by liuhuichao on 2017/7/27.
 */
public class IDataCallback implements AsyncCallback.DataCallback {
    @Override
    public void processResult(int rc, String path, Object ctx, byte[] data, Stat stat) {
        System.out.println("rc="+rc+" ;path="+path+" ;ctx="+ctx+" ;data="+data+" ;stat="+stat);
        System.out.println("string data="+new String(data));
        System.out.println("max version="+stat.getVersion());
    }
}

更新数据

• 同步设置数据

  zk.setData(path+"/lhc","lllhc".getBytes(),-1);//同步设置数据

• 异步设置数据

/**
 *
 * 同步/异步获取数据
 * Created by liuhuichao on 2017/7/27.
 */
public class GetData_API_Sync_Usage  implements Watcher{

    private static CountDownLatch conntedSamphore=new CountDownLatch(1);
    private static ZooKeeper zk=null;
    private static Stat stat=new Stat();
    @Override
    public void process(WatchedEvent watchedEvent) {
        if(Event.KeeperState.SyncConnected==watchedEvent.getState()){
            conntedSamphore.countDown();
        }else if(watchedEvent.getType()== Event.EventType.NodeCreated){
            System.out.println("node changed:"+watchedEvent.getPath());
        }

    }

    public static void main(String[] args) throws Exception{
        String path="/test-1";
       zk =new ZooKeeper("rc-zkp-datn-rse-nmg-ooz-woasis:2181",5000,new GetData_API_Sync_Usage());
        conntedSamphore.await();
        System.out.println("zk-19 连接成功！");
        //zk.create(path+"/lhc", "".getBytes(),ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
        List<String> children=zk.getChildren(path,new GetData_API_Sync_Usage());
        System.out.println("children node:"+children);
        //zk.setData(path+"/lhc","lllhc".getBytes(),-1);//同步设置数据
        zk.setData(path+"/lhc","lhc".getBytes(),-1,new IStatCallback(),null);
        zk.getData(path+"/lhc",true,new IDataCallback(),null);//异步获取数据
        Thread.sleep(Integer.MAX_VALUE);
    }
}

/**
 * 异步设置数据回调接口
 * Created by liuhuichao on 2017/7/27.
 */
public class IStatCallback implements AsyncCallback.StatCallback{
    @Override
    public void processResult(int rc, String path, Object ctx, Stat stat) {
        System.out.println("rc="+rc+" ;path="+path+" ;ctx="+ctx+" ;stat="+stat);
        if(rc==0){
            System.out.println("数据设置成功！");
        }
    }
}

检测节点是否存在

/**
 * 检测zk node
 * Created by liuhuichao on 2017/7/27.
 */
public class Exist_API_Sync_Usage implements Watcher{
    private static CountDownLatch connetedSamphore=new CountDownLatch(1);
    private static ZooKeeper zk=null;

    @Override
    public void process(WatchedEvent watchedEvent) {
        if(Event.KeeperState.SyncConnected==watchedEvent.getState()){
            connetedSamphore.countDown();
        }else if(Event.EventType.NodeCreated==watchedEvent.getType()){
            System.out.println("node created=="+watchedEvent.getPath());
        }else if(Event.EventType.NodeDataChanged==watchedEvent.getType()){
            System.out.println("node changed=="+watchedEvent.getPath());
        }else if(Event.EventType.NodeDeleted==watchedEvent.getType()){
            System.out.println("node deleted=="+watchedEvent.getPath());
        }
    }

    public static void main(String[] args)throws Exception {
        String path="/test-1";
        zk =new ZooKeeper("rc-zkp-datn-rse-nmg-ooz-woasis:2181",5000,new Exist_API_Sync_Usage());
        connetedSamphore.await();
        System.out.println("zk-19 连接成功！");
        Stat stat=zk.exists(path,new Exist_API_Sync_Usage());
        System.out.println("stat="+stat==null?"为空":"不为空");
        zk.setData(path,"".getBytes(),-1);
        Thread.sleep(Integer.MAX_VALUE);

    }
}