06_zookeeper原生Java API使用

/**
     * 客户端和zk服务端的连接是一个异步的过程
     * 当连接成功后，客户端会收到一个watch通知
     *
     * ZooKeeper(String connectString, int sessionTimeout, Watcher watcher,
     *          long sessionId, byte[] sessionPasswd, boolean canBeReadOnly)
     * 参数介绍
     * connectString：连接服务器的ip字符串
     *      比如："192.168.1.1:2181,192.168.1.2:2181,192.168.1.3:2181"
     *      可以是一个ip，也可以是多个ip，一个ip代表单机，多个ip代表集群
     *      也可以在ip后加路径
     * sessionTimeout：超时时间，心跳收不到了，那就超时
     * watcher：通知事件，如果有对应的事件触发，则会收到一个通知：如果不需要，那就设为null
     * sessionId：会话的id
     * sessionPasswd：会话密码，当会话丢失后，可以依据sessionId和sessionPasswd重新获取会话
     * canBeReadOnly：可读，当这个物理机节点断开后，还是可以读到数据的，只是不能写，
     *                此时数据被读取到的可能是旧数据，一般设置为false，不推荐使用
     *
     */
public ZooKeeper(String connectString, int sessionTimeout, Watcher watcher, long sessionId, byte[] sessionPasswd, boolean canBeReadOnly)

package com.zk.demo;

import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;

/**
 * Created by HigginCui on 2018/9/20.
 */
public classZkConnect implements Watcher{

    public static final String zkServerPath = "127.0.0.1:2181";

    public static final Integer timeout = 5000;

    /**
     * 客户端和zk服务端的连接是一个异步的过程
     * 当连接成功后，客户端会收到一个watch通知
     */
    public static voidmain(String[] args) throws Exception{
        ZooKeeper zk = new ZooKeeper(zkServerPath,timeout,newZkConnect());

        for (int i=0;i<20;i++) {
            Thread.sleep(10);  //休眠10ms，在这个过程中，连接状态会从CONNECTING--->CONNECTED
            System.out.println(i+"---"+zk.getState());
        }

    }

    @Override
    public voidprocess(WatchedEvent watchedEvent) {
        System.err.println("收到zk的watch通知----");
    }
}

packagecom.zk.demo;

importorg.apache.zookeeper.WatchedEvent;
importorg.apache.zookeeper.Watcher;
importorg.apache.zookeeper.ZooKeeper;

importjava.util.concurrent.CountDownLatch;

public class ZkConnect implementsWatcher{

    public static final String zkServerPath = "127.0.0.1:2181";

    public static final Integer timeout = 5000;

    private static CountDownLatch latch = new CountDownLatch(1);

    public static void main(String[] args) throwsException{
        ZooKeeper zk = new ZooKeeper(zkServerPath,timeout,newZkConnect());

        System.out.println("连接状态---" +zk.getState());
        latch.await();
        System.out.println("连接状态---" +zk.getState());

    }

    @Override
    public voidprocess(WatchedEvent watchedEvent) {
        System.err.println("收到zk的watch通知----");
        latch.countDown();
    }
}

/*** 
* String create(String path, byte[] data, List<ACL> acl, CreateMode createMode)
 * 
 * 同步或异步创建节点，都不支持子节点的递归操作，异步有一个callBack方法
 * 参数
 * path：创建的路径
 * data：存储的数据,byte[]类型
 * acl：权限控制策略
 *      Ids.OPEN_ACL_UNSAFE ---> world:anyone:crdwa
 *      CREATE_ALL_ACL ---> auth:user:password:cdrwa
 * createMode：节点类型，是一个枚举
 *      CreateMode.PERSISTENT：           持久节点
 *      CreateMode.PERSISTENT_SEQUENTIAL：持久顺序节点
 *      CreateMode.EPHEMERAL：            临时节点
 *      CreateMode.EPHEMERAL_SEQUENTIAL： 临时顺序节点
 */

packagecom.zk.demo;

import org.apache.zookeeper.*;
importjava.util.concurrent.CountDownLatch;

/*** Created by HigginCui on 2018/9/21.
 */
public class ZkNodeOperator implementsWatcher{


    private static ZooKeeper zooKeeper = null;

    public static final String zkServerPath = "127.0.0.1:2181";

    public static final Integer timeout = 5000;

    private static CountDownLatch latch = new CountDownLatch(1);

    publicZkNodeOperator() {
    }

    private static voidinit()  {
        try{
            zooKeeper = new ZooKeeper(zkServerPath,timeout,newZkNodeOperator());
            latch.await();
        }catch(Exception e){
            e.printStackTrace();
            if(zooKeeper!=null){
                try{
                    zooKeeper.close();
                }catch(InterruptedException e1){
                    e1.printStackTrace();
                }
            }
        }
    }

    public static void main(String[] args) throwsException{
        init();
//创建/testnode临时节点，包含数据为haha,权限是OPEN_ACL_UNSAFE，类型为临时节点
        zooKeeper.create("/testnode","haha".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.EPHEMERAL);
    }


    /*** 观察者
     */@Override
    public voidprocess(WatchedEvent event) {
        System.err.println("收到zk的watch通知----" +event.getPath()+"---"+event.getState());
        latch.countDown();

    }
}

packagecom.zk.demo;

import org.apache.zookeeper.*;
importjava.util.concurrent.CountDownLatch;

/*** Created by HigginCui on 2018/9/21.
 */
public class ZkNodeOperator implementsWatcher{


    private static ZooKeeper zooKeeper = null;

    public static final String zkServerPath = "127.0.0.1:2181";

    public static final Integer timeout = 5000;

    private static CountDownLatch latch = new CountDownLatch(1);

    publicZkNodeOperator() {
    }

    private static voidinit()  {
        try{
            zooKeeper = new ZooKeeper(zkServerPath,timeout,newZkNodeOperator());
            latch.await();
        }catch(Exception e){
            e.printStackTrace();
            if(zooKeeper!=null){
                try{
                    zooKeeper.close();
                }catch(InterruptedException e1){
                    e1.printStackTrace();
                }
            }
        }
    }

    public static void main(String[] args) throwsException{
        init();
        //create(String path, byte[] data, List<ACL> acl, CreateMode createMode, StringCallback cb, Object ctx)
        String ctx = "{'create':'success'}";
        zooKeeper.create("/testnode","haha".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT,newCreateNodeCallBack(),ctx);

        System.in.read();  //线程停在这里，等待回调线程的打印结果
}


    /*** 观察者
     */@Override
    public voidprocess(WatchedEvent event) {
        System.err.println("收到zk的watch通知----" +event.getPath()+"---"+event.getState());
        latch.countDown();

    }
}

/*** 创建节点回调通知类
 */
class CreateNodeCallBack implementsAsyncCallback.StringCallback{
    @Override
    public void processResult(inti, String path, Object ctx, String s1) {
        System.out.println("【回调方法】：创建节点的路径："+path);
        System.out.println("【回调方法】：ctx==="+(String)ctx);
    }
}

/*** path：节点路径
* data：修改后的数据
* version:版本号，这里的版本号必须是正要修改的节点数据的版本号！！
*/Stat setData(String path, byte[] data, int version)

Stat stat = zooKeeper.setData("/testnode", "Higgin".getBytes(), 1);
System.out.println("修改后数据的版本号为---"+stat.getVersion());

Stat stat = zooKeeper.setData("/testnode", "Higgin".getBytes(), 0);
System.out.println("修改后数据的版本号为---"+stat.getVersion());

/**
* 删除节点
* 注意：version版本号必须和要删除的节点数据的版本号一致
*/
public void delete(String path, int version)

zooKeeper.delete("/testnode",1);

public byte[] getData(String path, boolean watch, Stat stat) 
public byte[] getData(String path, Watcher watcher, Stat stat)
public voidgetData(String path, Watcher watcher, DataCallback cb, Object ctx)
public void getData(String path, boolean watch, DataCallback cb, Object ctx)

byte[] dateBytes = zooKeeper.getData("/testnode", true, null);
String str = newString(dateBytes);
System.err.println("获取的数据为==="+str);

public List<String>getChildren(String path, Watcher watcher)
public List<String>getChildren(String path, boolean watch, Stat stat)
public List<String>getChildren(String path, boolean watch, Stat stat) 
public voidgetChildren(String path, Watcher watcher, ChildrenCallback cb, Object ctx)
......

List<String> childList = zooKeeper.getChildren("/testnode", null);
for(String child : childList) {
    System.err.println("子节点=="+child);
}