Zookeeper客户端eclipse操作

eclipse客户端操作与LIiux命令行操作是一样的

Eclipse环境搭建

1）创建一个工程

2）解压zookeeper-3.4.10.tar.gz文件

3）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。

4）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  

一、开启hadoop106、haoop107、hadoop108集群

二、eclipse编写代码初始化客户端

package com.common.zk;

import java.io.IOException;

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

public class TestZookeeper {
	//连接zkServer
//获取zookeeper连接时所需要的服务器连接信息，格式为主机名：端口号
	private String connectString ="hadoop106:2181,hadoop107:2181,hadoop108:2181";
	//超时间设置
	private int sessionTimeout=2000;
	private ZooKeeper zkClient;
	
	//初始化zk客户端
	@Test
	public void initClient() throws IOException {
		zkClient=new ZooKeeper(connectString, sessionTimeout, new Watcher() {
			
			@Override
			public void process(WatchedEvent event) {
				// 收到事件通知后的回调函数（用户的业务逻辑）
				System.out.println(event.getType()+"\t"+event.getPath());				
			}
		});
	}
}

三、由此可以看出，初始化客户端成功

四、测试创建子节点

增加创建子节点方法，同时不要忘记把初始化客户端的测试方法改为before

package com.common.zk;

import java.io.IOException;

import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.junit.Before;
import org.junit.Test;


public class TestZookeeper {
	//连接zkServer
	private String connectString ="hadoop106:2181,hadoop107:2181,hadoop108:2181";
	//超时间设置
	private int sessionTimeout=2000;
	private ZooKeeper zkClient;
	
	//初始化zk客户端
	//修改为before，否则报空指针错误
	@Before
	public void initClient() throws IOException {
		zkClient=new ZooKeeper(connectString, sessionTimeout, new Watcher() {
			
			@Override
			public void process(WatchedEvent event) {
				System.out.println(event.getType()+"\t"+event.getPath());
				
			}
		});
	}
	
	//创建子节点
	//initClient此时应该修改为before
	@Test
	public void create() throws KeeperException, InterruptedException {
		//创建子节点你的路径是/xz 创建内容是xiaozhan,要求是bytes类型，创建的权限是open_acl_unsafe,创建模式是永久节点
		String path=zkClient.create("/xz", "xiaozhan".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
		System.out.println(path);
	}
}

运行Junit测试，查看结果

路径成功输出

五、获取子节点信息

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

运行

六、设置监听子节点

package com.common.zk;

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

import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.junit.Before;
import org.junit.Test;


public class TestZookeeper {
	//连接zkServer
	private String connectString ="hadoop106:2181,hadoop107:2181,hadoop108:2181";
	//超时间设置
	private int sessionTimeout=2000;
	private ZooKeeper zkClient;
	
	//初始化zk客户端
	//修改为before，否则报空指针错误
	@Before
	public void initClient() throws IOException {
		zkClient=new ZooKeeper(connectString, sessionTimeout, new Watcher() {
			
			@Override
			public void process(WatchedEvent event) {
				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 | InterruptedException e) {
					e.printStackTrace();
				}
			}
		});
	}
	
	//创建子节点
	//initClient此时应该修改为before
	
	public void create() throws KeeperException, InterruptedException {
		//创建子节点你的路径是/xz 创建内容是xiaozhan,要求是bytes类型，创建的权限是open_acl_unsafe,创建模式是永久节点
		String path=zkClient.create("/xz", "xiaozhan".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
		System.out.println(path);
	}
	
	//获取子节点信息
	@Test
	public void getChild() throws KeeperException, InterruptedException {
		List<String> zkchild=zkClient.getChildren("/", true);//true代表监听,调用上面的initClient()的watcher()方法
//		for (String child : zkchild) {
//			System.out.println(child);
//		}

//挂起线程，保证监听的进程不会死掉
		Thread.sleep(Long.MAX_VALUE);
	}
}

run

在命令行创建yy节点后

控制台监听得到

在命令行删除节点yy

控制台监听到的结果

七、判断节点是否存在

八、动态模拟服务器上下线

 对于zookeeper集群而言，服务端和客户端都是客户端，只不过一个是写请求，一个是读请求