zookeeper java API开发

安装与入门

pom.xml

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>RELEASE</version>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.8.2</version>
</dependency>
<dependency>
    <groupId>org.apache.zookeeper</groupId>
    <artifactId>zookeeper</artifactId>
    <version>3.5.7</version>
</dependency>

log4j.properties

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 

节点增删改代码

package com.chen.zk;

import org.apache.zookeeper.*;
import org.apache.zookeeper.data.Stat;
import org.junit.Before;
import org.junit.Test;

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

public class zkClient {
    private String connectString = "hadoop100:2181,hadoop101:2181,hadoop102:2181";
    private int sessionTimeout = 2000;// 2秒
    private ZooKeeper zooKeeper;

    @Before
    public void init() throws IOException {
        zooKeeper = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
            @Override
            //监听
            public void process(WatchedEvent watchedEvent) {
//                System.out.println("-------------------------------");
//                List<String> children = null;
//                try {
//                    children = zooKeeper.getChildren("/", true);
//                    for (String child : children) {
//                        System.out.println(child);
//                    }
//                    System.out.println("-------------------------------");
//                } catch (KeeperException e) {
//                    e.printStackTrace();
//                } catch (InterruptedException e) {
//                    e.printStackTrace();
//                }
            }
        });
    }

    //创建节点
    @Test
    public void create() throws KeeperException, InterruptedException {
        String node = zooKeeper.create("/chen", "chendata".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
    }

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

    //判断节点存在，不存在返回null
    @Test
    public void exist() throws KeeperException, InterruptedException {
        Stat stat = zooKeeper.exists("/chen", false);
        System.out.println("---------------"+stat);
    }
}