zookeeper的API应用

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eclipse环境搭建

拷贝zookeeper-3.4.10.jar、jline-0.9.94.jar、log4j-1.2.16.jar、netty-3.10.5.Final.jar、slf4j-api-1.6.1.jar、slf4j-log4j12-1.6.1.jar到工程的lib目录。并build一下，导入工程。
拷贝log4j.properties文件到项目根目录

log4j.rootLogger=INFO, stdout  
log4j.appender.stdout=org.apache.log4j.ConsoleAppender  
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout  
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n  
log4j.appender.logfile=org.apache.log4j.FileAppender  
log4j.appender.logfile.File=target/spring.log  
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout  
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n  

客户端代码

创建ZooKeeper客户端

package com.zyd.zook;
import java.io.IOException;

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

public class TestZookeeper {
	//连接zkServer
	private String connectString = "testnote01,testnote02,testnote03";
	//超时间设置
	private int sessionTimeout = 2000;
	ZooKeeper zkClient;
	
	//初始化客户端
	@Test
	public void initClient() throws IOException {
		zkClient =new ZooKeeper(connectString, sessionTimeout, new Watcher(){

			@Override
			public void process(WatchedEvent event) {
			System.out.println(event.getType()+"--------"+event.getPath());
			}
			
		});
	}
}

结果

2018-11-17 11:01:32,638 INFO [org.apache.zookeeper.ZooKeeper] - Initiating client connection, connectString=testnote01,testnote02,testnote03 sessionTimeout=2000 watcher=com.zyd.zook.TestZookeeper$1@64650ddb

创建子节点

/**
	 * 创建子节点
	 * @throws InterruptedException 
	 * @throws KeeperException 
	 */
	@Test
	public void create() throws KeeperException, InterruptedException{
		//路径 数据 权限(通过接口Ids分别所有)节点类型(临时的 临时带序列号的 永久的 永久带序列号的,具体看源码)
	String path =	zkClient.create("/zyd", "shuai".getBytes(), Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT);
		
		System.out.println(path);
	}

修改创建客户端为@Test
结果

 2018-11-17 11:15:41,588 INFO [org.apache.zookeeper.ClientCnxn] - Session establishment complete on server testnote01/192.168.18.50:2181, sessionid = 0x1672083bdd80004, negotiated timeout = 4000
  None--------null
/zyd

获取节点信息

监听模式为false

//获取子节点
	@Test
	public void getChild() throws KeeperException, InterruptedException {
		List<String> children = zkClient.getChildren("/", false);
		for (String child : children) {
			System.out.println(child);
		}
	}

结果

  2018-11-17 11:37:44,417 INFO [org.apache.zookeeper.ClientCnxn] - Session establishment complete on server testnote03/192.168.18.52:2181, sessionid = 0x3671e81bdeb0000, negotiated timeout = 4000
  None--------null
zookeeper
zyd
app1

开启监听模式

//获取子节点
	@Test
	public void getChild() throws KeeperException, InterruptedException {
		List<String> children = zkClient.getChildren("/", true);
		for (String child : children) {
			System.out.println(child);
		}
		Thread.sleep(Long.MAX_VALUE);
	}

调用的是客户端的监听方法

@Override
			public void process(WatchedEvent event) {
//			System.out.println(event.getType()+"--------"+event.getPath());
			
			System.out.println("------------start--------------");
			List<String> children;
			try {
				children = zkClient.getChildren("/", true);
				for (String child : children) {
					System.out.println(child);
				}
				System.out.println("------------end--------------");
			} catch (KeeperException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			}
			
		});
	}

判断子节点是否存在

//判断节点是否存在
	
	@Test
	public void exist() throws KeeperException, InterruptedException{
		Stat stat = zkClient.exists("/zyd", false);
		System.out.println(stat == null ? "not exist":"exist");
	}
}