Zookeeper入门(七)之Java连接Zookeeper

Java操作Zookeeper很简单，但是前提要把包导对。

关于Zookeeper的Linux环境搭建可以参考我的这篇博客:Linux环境下Zookeeper安装

下面进入正题:

一、导入依赖

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>cn.zookeeper</groupId>
  <artifactId>zookeeper_demo</artifactId>
  <version>0.0.1-SNAPSHOT</version>

<!-- https://mvnrepository.com/artifact/org.apache.zookeeper/zookeeper -->

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

二、编写工具类代码和测试代码

package zookeeper_demo;

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{

   private ZooKeeper zookeeper;
    /**
     * 超时时间
     */
   private static final int SESSION_TIME_OUT = 2000;
   private CountDownLatch countDownLatch = new CountDownLatch(1);

   public void process(WatchedEvent event) {
      if (event.getState() == KeeperState.SyncConnected) {
         System.out.println("Watch received event");
         countDownLatch.countDown();
      }
   }

   /**连接zookeeper
    * @param host
    * @throws Exception
    */
   public void connectZookeeper(String host) throws Exception{
      zookeeper = new ZooKeeper(host, SESSION_TIME_OUT, this);
      countDownLatch.await();
      System.out.println("zookeeper connection success");
   }

   /**
    * 创建节点
    * @param path
    * @param data
    * @throws Exception
    */
   public String createNode(String path,String data) throws Exception{
      return this.zookeeper.create(path, data.getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
   }

   /**
    * 获取路径下所有子节点
    * @param path
    * @return
    * @throws KeeperException
    * @throws InterruptedException
    */
   public List<String> getChildren(String path) throws KeeperException, InterruptedException{
      List<String> children = zookeeper.getChildren(path, false);
      return children;
   }

   /**
    * 获取节点上面的数据
    * @param path  路径
    * @return
    * @throws KeeperException
    * @throws InterruptedException
    */
   public String getData(String path) throws KeeperException, InterruptedException{
      byte[] data = zookeeper.getData(path, false, null);
      if (data == null) {
         return "";
      }
      return new String(data);
   }

   /**
    * 设置节点信息
    * @param path  路径
    * @param data  数据
    * @return
    * @throws KeeperException
    * @throws InterruptedException
    */
   public Stat setData(String path,String data) throws KeeperException, InterruptedException{
      Stat stat = zookeeper.setData(path, data.getBytes(), -1);
      return stat;
   }

   /**
    * 删除节点
    * @param path
    * @throws InterruptedException
    * @throws KeeperException
    */
   public void deleteNode(String path) throws InterruptedException, KeeperException{
      zookeeper.delete(path, -1);
   }

   /**
    * 获取创建时间
    * @param path
    * @return
    * @throws KeeperException
    * @throws InterruptedException
    */
   public String getCTime(String path) throws KeeperException, InterruptedException{
      Stat stat = zookeeper.exists(path, false);
      return String.valueOf(stat.getCtime());
   }

   /**
    * 获取某个路径下孩子的数量
    * @param path
    * @return
    * @throws KeeperException
    * @throws InterruptedException
    */
   public Integer getChildrenNum(String path) throws KeeperException, InterruptedException{
      int childenNum = zookeeper.getChildren(path, false).size();
      return childenNum;
   }
   /**
    * 关闭连接
    * @throws InterruptedException
    */
   public void closeConnection() throws InterruptedException{
      if (zookeeper != null) {
         zookeeper.close();
      }
   }
   public static void main(String[] args) throws Exception {
       BaseZookeeper zookeeper = new BaseZookeeper();
       zookeeper.connectZookeeper("192.168.126.128:2181");
       List<String> children = zookeeper.getChildren("/");
       System.out.println(children);
   }
}

完成以上两步，即可完成Java连接并对Zookeeper的简单操作。