ZooKeeper之java客户端访问-入门介绍

时间 2014-03-22 22:42:48  CSDN博客
原文  http://blog.csdn.net/fengspg/article/details/21805075
主题 ZooKeeper Java
上篇简单的介绍了单点部署ZooKeeper及节点管理。

这里介绍下如何通过java客户端进行各个节点的管理。

具体就不一一介绍，相信从代码的注释中就可以看明白

首先创建一个zookeeper的基础类，里面包含了基本的节点管理方法，如下：

package com.zktest.newtest;

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

import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.KeeperState;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;

public class BaseZookeeper implements Watcher
{

  public ZooKeeper zooKeeper;

  private static final int SESSION_TIME_OUT = 2000;

  private CountDownLatch countDownLatch = new CountDownLatch(1);

  /**
   * 连接zookeeper
   *
   * @param host
   * @throws IOException
   * @throws InterruptedException
   */
  public void connectZookeeper(String host) throws IOException,
      InterruptedException
  {
    zooKeeper = new ZooKeeper(host, SESSION_TIME_OUT, this);
    countDownLatch.await();
    System.out.println("zookeeper connect ok");

  }

  /**
   * 实现watcher的接口方法，当连接zookeeper成功后，zookeeper会通过此方法通知watcher<br>
   * 此处为如果接受到连接成功的event，则countDown，让当前线程继续其他事情。
   */
  @Override
  public void process(WatchedEvent event)
  {
    if (event.getState() == KeeperState.SyncConnected)
    {
      System.out.println("watcher received event");
      countDownLatch.countDown();
    }
  }

  /**
   * 根据路径创建节点，并且设置节点数据
   * @param path
   * @param data
   * @return
   * @throws KeeperException
   * @throws InterruptedException
   */
  public String createNode(String path, byte[] data) throws KeeperException,
      InterruptedException
  {
    return this.zooKeeper.create(path, data, Ids.OPEN_ACL_UNSAFE,
        CreateMode.PERSISTENT);
  }

  /**
   * 根据路径获取所有孩子节点
   *
   * @param path
   * @return
   * @throws KeeperException
   * @throws InterruptedException
   */
  public List<String> getChildren(String path) throws KeeperException,
      InterruptedException
  {
    return this.zooKeeper.getChildren(path, false);
  }

  public Stat setData(String path, byte [] data, int version) throws KeeperException, InterruptedException
  {
    return this.zooKeeper.setData(path, data, version);
  }
 
  /**
   * 根据路径获取节点数据
   *
   * @param path
   * @return
   * @throws KeeperException
   * @throws InterruptedException
   */
  public byte[] getData(String path) throws KeeperException,
      InterruptedException
  {
    return this.zooKeeper.getData(path, false, null);
  }

  /**
   * 删除节点
   *
   * @param path
   * @param version
   * @throws InterruptedException
   * @throws KeeperException
   */
  public void deletNode(String path, int version)
      throws InterruptedException, KeeperException
  {
    this.zooKeeper.delete(path, version);
  }

  /**
   * 关闭zookeeper连接
   *
   * @throws InterruptedException
   */
  public void closeConnect() throws InterruptedException
  {
    if (null != zooKeeper)
    {
      zooKeeper.close();
    }
  }

}
创建客户端进行测试，代码如下：
package com.spg.zktest.newtest;

import java.io.IOException;
import java.util.Arrays;
import java.util.List;

import org.apache.zookeeper.KeeperException;

public class Client
{

  /**
   * @param args
   * @throws InterruptedException
   * @throws IOException
   * @throws KeeperException
   */
  public static void main(String[] args) throws IOException, InterruptedException, KeeperException
  {
    BaseZookeeper baseZookeeper = new BaseZookeeper();
   
    String host = "192.168.183.128:2181";
   
    // 连接zookeeper
    baseZookeeper.connectZookeeper(host);
    System.out.println("--------connect zookeeper ok-----------");
   
    // 创建节点
    byte [] data = {1, 2, 3, 4, 5};
    String result = baseZookeeper.createNode("/test", data);
    System.out.println(result);
    System.out.println("--------create node ok-----------");
   
    // 获取某路径下所有节点
    List<String> children = baseZookeeper.getChildren("/");
    for (String child : children)
    {
      System.out.println(child);
    }
    System.out.println("--------get children ok-----------");
   
    // 获取节点数据
    byte [] nodeData = baseZookeeper.getData("/test");
    System.out.println(Arrays.toString(nodeData));
    System.out.println("--------get node data ok-----------");
   
    // 更新节点数据
    data = "test data".getBytes();
    baseZookeeper.setData("/test", data, 0);
    System.out.println("--------set node data ok-----------");
   
    nodeData = baseZookeeper.getData("/test");
    System.out.println(Arrays.toString(nodeData));
    System.out.println("--------get node new data ok-----------");
   
    baseZookeeper.closeConnect();
    System.out.println("--------close zookeeper ok-----------");
  }

}
从命令行中看操作后的结果，如下：
1：根目录下节点


2：查看test节点信息


OK，测试结果到此结束。