Good Zookeeper Tutorial with Java client

参考： https://stackoverflow.com/questions/33524537/good-zookeeper-tutorial-with-java-client

I was trying to use Zookeeper in our project. Could run the server..Even test it using zkcli.sh .. All good.. But couldn't find a good tutorial for me to connect to this server using Java ! All I need in Java API is a method



-----------------------------------------

Finally, this is the simplest and most basic program I came up with which will help you with ZooKeeper "Getting Started":

package com.fly.app;

import java.util.Date;
import java.util.List;
import java.util.concurrent.CountDownLatch;

import org.apache.zookeeper.CreateMode;
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;

public class ZkConnect {
private ZooKeeper zk;
private CountDownLatch connSignal = new CountDownLatch(0);

//host should be 127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002
public ZooKeeper connect(String host) throws Exception {
zk = new ZooKeeper(host, 3000, new Watcher() {
public void process(WatchedEvent event) {
if (event.getState() == KeeperState.SyncConnected) {
connSignal.countDown();
}
}
});
connSignal.await();
return zk;
}

public void close() throws InterruptedException {
zk.close();
}

public void createNode(String path, byte[] data) throws Exception
{
zk.create(path, data, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
}

public void updateNode(String path, byte[] data) throws Exception
{
zk.setData(path, data, zk.exists(path, true).getVersion());
}

public void deleteNode(String path) throws Exception
{
zk.delete(path,  zk.exists(path, true).getVersion());
}

public static void main (String args[]) throws Exception
{
ZkConnect connector = new ZkConnect();
ZooKeeper zk = connector.connect("54.169.132.0,52.74.51.0");
String newNode = "/deepakDate"+new Date();
connector.createNode(newNode, new Date().toString().getBytes());
List<String> zNodes = zk.getChildren("/", true);
for (String zNode: zNodes)
{
System.out.println("ChildrenNode " + zNode);
}
byte[] data = zk.getData(newNode, true, zk.exists(newNode, true));
System.out.println("GetData before setting");
for ( byte dataPoint : data)
{
System.out.print ((char)dataPoint);
}

System.out.println("GetData after setting");
connector.updateNode(newNode, "Modified data".getBytes());
data = zk.getData(newNode, true, zk.exists(newNode, true));
for ( byte dataPoint : data)
{
System.out.print ((char)dataPoint);
}
connector.deleteNode(newNode);
}

}

　　pom.xml

<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>com.fly.app</groupId>
<artifactId>new-app</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>new-app</name>
<url>http://maven.apache.org</url>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.6</maven.compiler.source>
<maven.compiler.target>1.6</maven.compiler.target>

</properties>

<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.4.6</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>2.3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<artifactId>maven-assembly-plugin</artifactId>
<version>2.4</version>
<configuration>
<descriptorRefs>
</configuration>
<executions>
<execution>
<id>make-assembly</id>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>

</project>

　　编译后，运行的结果：



项目的结构：



执行 mvn clean 之后：



执行 mvn assembly:assembly 之后，编译后的结果为：



两个jar包的内容是不一样的。

java -cp target/new-app-0.0.1-SNAPSHOT-jar-with-dependencies.jar com.fly.app.ZkConnect



或者：java -cp target/new-app-0.0.1-SNAPSHOT.jar:/data/tools/zookeeper-3.4.11/lib/slf4j-api-1.6.1.jar:/data/tools/zookeeper-3.4.11/zookeeper-3.4.11.jar:/data/tools/zookeeper-3.4.11/lib/*.jar com.fly.app.ZkConnect