西柚的大数据从踩坑到放弃

西柚的大数据从踩坑到放弃

zookeeper java api

申明一下本系列纯做个人笔记记录用，不会涉及太多原理讲解和算法或者运维知识，且内容浅显，请有需要的自行查阅资料
上回说到客户端shell操作，对节点和信息进行一个维护，这回来看怎么用java代码实现这块。

1. idea新建maven项目，依赖：

<dependencies><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>keeper</groupId><artifactId>zookeeper</artifactId><version>3.4.14</version></dependency>
</dependencies>

2. resource新建log4j.properties 还是直接跑吧

Logger=INFO, stdout, logfile
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/log.log
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n

3.junit代码，均经过测试可运行

package zkmanage;import keeper.*;
import keeper.data.Stat;
import org.junit.Before;
import org.junit.Test;import java.io.IOException;
import java.util.List;public class TestZK {private String connectStr = "ubuntu001:2181,ubuntu002:2181,ubuntu003:2181";private int sessionTimeout = 20000;private ZooKeeper zkClient;//初始化client//@Test@Beforepublic void init() throws IOException {zkClient = new ZooKeeper(connectStr, sessionTimeout, new Watcher() {//监听的时候需要编写此处public void process(WatchedEvent watchedEvent) {System.out.println("-------------------监听开始");List<String> children = null;try {children = Children("/", true);} catch (KeeperException e) {e.printStackTrace();} catch (InterruptedException e) {e.printStackTrace();}for (String child: children) {System.out.println(child);}System.out.println("-------------------监听结束");}});}//创建节点@Testpublic void createNode() throws KeeperException, InterruptedException, IOException {String path &#ate("/leafznode2", "222".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);System.out.println(path);}//获得节点数据@Testpublic void getData() throws KeeperException, InterruptedException {List<String> children = Children("/", false);for (String child: children) {System.out.println(child);}}//获得节点数据并监听节点@Testpublic void getDataAndWatch() throws KeeperException, InterruptedException {List<String> children = Children("/", true);for (String child: children) {System.out.println(child);}Thread.sleep(Long.MAX_VALUE);//启动起来以后去集群上做一些变动，这边程序可以监听到}//判断znode是否存在@Testpublic void exist() throws KeeperException, InterruptedException {Stat stat = ists("/leafznode1", false);System.out.println(stat);System.out.println(stat == null?"not exist":"exist");}
}