Zookeeper Java API

xywuyiba7

续前话,Zookeeper的环境已经搭建好了.接下来就是利用Java实现与zookeeper的连接,达到和ZOOKEEPER_HOME\bin\zkCli.sh中的部分基础功能.
具体的zookeeper的安装见ZooKeeper起步配置.

import java.io.IOException;
import java.util.concurrent.CountDownLatch;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.Watcher.Event.KeeperState;
/**
* @author ruodao
* @since 1.0
* 2010-2-18 下午08:57:36
*/
public class AbstractZooKeeper implements Watcher {
private static final int SESSION_TIME = 2000;
protected ZooKeeper  zooKeeper;
protected CountDownLatch countDownLatch= new CountDownLatch(1);
public void connect(String hosts) throws IOException, InterruptedException{
zooKeeper = new ZooKeeper(hosts,SESSION_TIME,this);
countDownLatch.await();
}
public void process(WatchedEvent event) {
if(event.getState() == KeeperState.SyncConnected){
countDownLatch.countDown();
}
}
public void close() throws InterruptedException{
zooKeeper.close();
}
}


下面一段代码实现了简单的操作,添加,获取数据,获取子节点.

import java.util.Arrays;
import java.util.List;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.ZooDefs.Ids;
/**
* @author ruodao
* @since 1.0
* 2010-2-18 下午09:03:21
*/
public class ZooKeeperOperator extends AbstractZooKeeper {
/**
* 创建持久态的znode,比支持多层创建.比如在创建/parent/child的情况下,无/parent.无法通过.
* @param path eg:  /parent/child1
* @param data
* @throws InterruptedException
* @throws KeeperException
*/
public void create(String path,byte[] data) throws KeeperException, InterruptedException{
this.zooKeeper.create(path, data, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT/*此处创建的为持久态的节点,可为瞬态*/);
}

/**
* 获取节点的孩子信息
* @param path
* @throws KeeperException
* @throws InterruptedException
*/
public void getChild(String path) throws KeeperException, InterruptedException{
try {
List<String> children = this.zooKeeper.getChildren(path, false);
if (children.isEmpty()) {
System.out.printf("没有节点在%s中.", path);
return;
}else{
System.out.printf("节点%s中存在的节点:\n", path);
for(String child: children){
System.out.println(child);
}
}
} catch (KeeperException.NoNodeException e) {
System.out.printf("%s节点不存在.", path);
throw e;
}
}
public byte[] getData(String path) throws KeeperException, InterruptedException {
returnthis.zooKeeper.getData(path, false,null);
}
}


main函数

public static void main(String[] args) {
try {
ZooKeeperOperator zkoperator = new ZooKeeperOperator();
zkoperator.connect("192.168.0.115");
byte[] data = new byte[]{'d','a','t','a'};
zkoperator.create("/root",null);
System.out.println(Arrays.toString(zkoperator.getData("/root")));
zkoperator.create("/root/child1",data);
System.out.println(Arrays.toString(zkoperator.getData("/root/child1")));
zkoperator.create("/root/child2",data);
System.out.println(Arrays.toString(zkoperator.getData("/root/child2")));
System.out.println("节点孩子信息:");
zkoperator.getChild("/root");
zkoperator.close();
} catch (Exception e) {
e.printStackTrace();
}
}

到这里,一个简单的程序已经可以运行了.以下是linux上的截图.