(原) 2.1 Zookeeper原生API使用

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Zookeeper原生API使用

1、jar包引入，演示版本为3.4.6，非maven项目，可以下载jar包导入到项目中

<dependency>      <groupId>org.apache.zookeeper</groupId>      <artifactId>zookeeper</artifactId>      <version>3.4.6</version></dependency>

2、创建zookeeper连接

　　ZooKeeper(java.lang.String connectString, int sessionTimeout, org.apache.zookeeper.Watcher watcher) 

• • connectString：zookeeper服务地址，例如“192.168.117.128:2181”
  • sessionTimeout ：超时时间，单位为毫秒
  • watcher：实现org.apache.zookeeper.Watcher接口的实现类，需实现process(WatchedEvent watchedEvent) 方法

　　ZooKeeper zooKeeper = new ZooKeeper("192.168.117.128:2181",5000, new MyWatcher());

示例代码：

import org.apache.zookeeper.WatchedEvent;import org.apache.zookeeper.Watcher;import org.apache.zookeeper.ZooKeeper;import java.io.IOException;/** * * zookeeper连接 */public class CreateSession implements Watcher{  private static ZooKeeper zooKeeper;  @Override  public void process(WatchedEvent watchedEvent) {    if(watchedEvent.getState().equals(Event.KeeperState.SyncConnected)) {      doBus();    }    System.out.println("接收内容："+watchedEvent.toString());  }  private void doBus() {    System.out.println("做业务！");  }  public static void main(String[] args) {    try {      zooKeeper = new ZooKeeper("192.168.117.128:2181",5000, new CreateSession());      System.out.println(zooKeeper.getState());      Thread.sleep(5000);    } catch (IOException e) {      e.printStackTrace();    } catch (InterruptedException e) {      e.printStackTrace();    }  }}

　　ps:此处没有新创建新的java类实现Watcher,而是直接在本类中实现Watcher接口并重写process方法

3、同步创建

　　create(java.lang.String path, byte[] data, java.util.List<org.apache.zookeeper.data.ACL> acl, org.apache.zookeeper.CreateMode createMode)

• • path：创建节点路径，需保证父节点已存在
  • data：节点数据
  • acl:权限列表
    • 提供默认的权限OPEN_ACL_UNSAFE、CREATOR_ALL_ACL、READ_ACL_UNSAFE
      • OPEN_ACL_UNSAFE：完全开放
      • CREATOR_ALL_ACL：创建该znode的连接拥有所有权限
      • READ_ACL_UNSAFE：所有的客户端都可读
    • 自定义权限　　

      ACL aclIp = new ACL(ZooDefs.Perms.READ,new Id("ip","127.0.0.1"));        ACL aclDigest = new ACL(ZooDefs.Perms.READ| ZooDefs.Perms.WRITE,            new Id("digest", DigestAuthenticationProvider.generateDigest("id:pass")));

      
      
    • session设置权限　

      zk.addAuthInfo("digest", "id:pass".getBytes());　　

  • createMode:节点类型
    • PERSISTENT：持久化节点
    • PERSISTENT_SEQUENTIAL：持久化有序节点
    • EPHEMERAL：临时节点（连接断开自动删除）
    • EPHEMERAL_SEQUENTIAL：临时有序节点（连接断开自动删除）

示例代码：　　

import org.apache.zookeeper.*;import org.apache.zookeeper.data.ACL;import org.apache.zookeeper.data.Id;import org.apache.zookeeper.server.auth.DigestAuthenticationProvider;import java.io.IOException;import java.security.NoSuchAlgorithmException;/** * 创建节点(同步) * Created by scot on 2016/6/8. */public class CreateSessionSync implements Watcher{  private static ZooKeeper zooKeeper;  @Override  public void process(WatchedEvent watchedEvent) {    if(watchedEvent.getState().equals(Event.KeeperState.SyncConnected)) {      doBus();    }    System.out.println("接收内容："+watchedEvent.toString());  }  private void doBus() {    try {      if(null != zooKeeper.exists("/note_scot/note_scot_a",false)) {        System.out.println("/note_scot/note_scot_a 节点已存在");        return;      }      String path = zooKeeper.create("/note_scot/note_scot_a","aa".getBytes(),          ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);      /*权限相关      try {        ACL aclIp = new ACL(ZooDefs.Perms.READ,new Id("ip","127.0.0.1"));        ACL aclDigest = new ACL(ZooDefs.Perms.READ| ZooDefs.Perms.WRITE,            new Id("digest", DigestAuthenticationProvider.generateDigest("id:pass")));        zooKeeper.addAuthInfo("digest", "id:pass".getBytes());　      } catch (NoSuchAlgorithmException e) {        e.printStackTrace();      }*/      System.out.println("zookeeper return:" + path);    } catch (KeeperException e) {      e.printStackTrace();    } catch (InterruptedException e) {      e.printStackTrace();    }  }  public static void main(String[] args) {    try {      zooKeeper = new ZooKeeper("192.168.117.128:2181",5000, new CreateSessionSync());      System.out.println(zooKeeper.getState());      Thread.sleep(5000);    } catch (IOException e) {      e.printStackTrace();    } catch (InterruptedException e) {      e.printStackTrace();    }  }}

4、异步创建

　　create(java.lang.String path, byte[] data, java.util.List<org.apache.zookeeper.data.ACL> acl,

　　　　　 org.apache.zookeeper.CreateMode createMode, org.apache.zookeeper.AsyncCallback.StringCallback cb, java.lang.Object ctx) 

• • StringCallback cb：回调接口，执行创建操作后，结果以及数据发送到此接口的实现类中
  • Object ctx：自定义回调数据，在回调实现类可以获取此数据

示例代码：

import org.apache.zookeeper.*;import java.io.IOException;/** * 创建节点(异步) * Created by scot on 2016/6/8. */public class CreateSessionASync implements Watcher{  private static ZooKeeper zooKeeper;  @Override  public void process(WatchedEvent watchedEvent) {    if(watchedEvent.getState().equals(Event.KeeperState.SyncConnected)) {      doBus();    }    System.out.println("接收内容："+watchedEvent.toString());  }  private void doBus() {      zooKeeper.create("/note_scot/note_scot_b","aa".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,          CreateMode.PERSISTENT_SEQUENTIAL,new IStringCallBack(),"testAsync");  }  public static void main(String[] args) {    try {      zooKeeper = new ZooKeeper("192.168.117.128:2181",5000, new CreateSessionASync());      System.out.println(zooKeeper.getState());      Thread.sleep(5000);    } catch (IOException e) {      e.printStackTrace();    } catch (InterruptedException e) {      e.printStackTrace();    }  }  static class IStringCallBack implements AsyncCallback.StringCallback {    @Override    public void processResult(int i, String s, Object o, String s2) {      System.out.println("i="+i);//创建成功返回0      System.out.println("s="+s);//自定义节点名称      System.out.println("o="+o);//自定义回调数据      System.out.println("s2="+s2);//最终节点名称（顺序节点最终名称与自定义名称不同）    }  }}

原标题：(原) 2.1 Zookeeper原生API使用

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