Java實現與ZooKeeper的連線
阿新 • • 發佈：2019-01-03
序言
續上一篇的 ZooKeeper安裝執行 這裡採用ZooKeeper的Java API進行連線。
Java實現
新建一個類實現介面Watcher. 是指：
This interface specifies the public interface an event handler class must implement. A ZooKeeper client will get various events from the ZooKeepr server it connects to. An application using such a client handles these events by registering a callback object with the client. The callback object is expected to be an instance of a class that implements Watcher interface.
/** * AbstractZooKeeper.java * 版權所有(C) 2013 * 建立:cuiran 2013-01-16 14:59:44 */ package com.zoo.demo; import java.io.IOException; import java.util.concurrent.CountDownLatch; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.zookeeper.WatchedEvent; import org.apache.zookeeper.Watcher; import org.apache.zookeeper.ZooKeeper; import org.apache.zookeeper.Watcher.Event.KeeperState; /** * TODO * @author cuiran * @version TODO */ public class AbstractZooKeeper implements Watcher { private static Log log = LogFactory.getLog(AbstractZooKeeper.class.getName()); //快取時間 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(); } /* (non-Javadoc) * @see org.apache.zookeeper.Watcher#process(org.apache.zookeeper.WatchedEvent) */ @Override public void process(WatchedEvent event) { // TODO Auto-generated method stub if(event.getState()==KeeperState.SyncConnected){ countDownLatch.countDown(); } } public void close() throws InterruptedException{ zooKeeper.close(); } }
然後寫一些操作和main方法
/** * ZooKeeperOperator.java * 版權所有(C) 2013 * 建立:cuiran 2013-01-16 15:03:40 */ package com.zoo.demo; import java.util.Arrays; import java.util.List; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.zookeeper.CreateMode; import org.apache.zookeeper.KeeperException; import org.apache.zookeeper.ZooDefs.Ids; /** * TODO * @author cuiran * @version TODO */ public class ZooKeeperOperator extends AbstractZooKeeper { private static Log log = LogFactory.getLog(ZooKeeperOperator.class.getName()); /** * *<b>function:</b>建立持久態的znode,比支援多層建立.比如在建立/parent/child的情況下,無/parent.無法通過 *@author cuiran *@createDate 2013-01-16 15:08:38 *@param path *@param data *@throws KeeperException *@throws InterruptedException */ public void create(String path,byte[] data)throws KeeperException, InterruptedException{ /** * 此處採用的是CreateMode是PERSISTENT 表示The znode will not be automatically deleted upon client's disconnect. * EPHEMERAL 表示The znode will be deleted upon the client's disconnect. */ this.zooKeeper.create(path, data, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT); } /** * *<b>function:</b>獲取節點資訊 *@author cuiran *@createDate 2013-01-16 15:17:22 *@param path *@throws KeeperException *@throws InterruptedException */ public void getChild(String path) throws KeeperException, InterruptedException{ try{ List<String> list=this.zooKeeper.getChildren(path, false); if(list.isEmpty()){ log.debug(path+"中沒有節點"); }else{ log.debug(path+"中存在節點"); for(String child:list){ log.debug("節點為："+child); } } }catch (KeeperException.NoNodeException e) { // TODO: handle exception throw e; } } public byte[] getData(String path) throws KeeperException, InterruptedException { return this.zooKeeper.getData(path, false,null); } public static void main(String[] args) { try { ZooKeeperOperator zkoperator = new ZooKeeperOperator(); zkoperator.connect("192.168.0.138"); byte[] data = new byte[]{'a','b','c','d'}; // 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"))); String zktest="ZooKeeper的Java API測試"; zkoperator.create("/root/child3", zktest.getBytes()); log.debug("獲取設定的資訊："+new String(zkoperator.getData("/root/child3"))); System.out.println("節點孩子資訊:"); zkoperator.getChild("/root"); zkoperator.close(); } catch (Exception e) { e.printStackTrace(); } } }
最後執行結果：
2013-01-16 15:26:04:INFO org.apache.zookeeper.ZooKeeper - Client environment:user.name=Administrator
2013-01-16 15:26:04:INFO org.apache.zookeeper.ZooKeeper - Client environment:user.home=C:\Documents and Settings\Administrator
2013-01-16 15:26:04:INFO org.apache.zookeeper.ZooKeeper - Client environment:user.dir=D:\workspace\stormdemo1
2013-01-16 15:26:04:INFO org.apache.zookeeper.ZooKeeper - Initiating client connection, connectString=192.168.0.138 sessionTimeout=2000 [email protected]
2013-01-16 15:26:04:INFO org.apache.zookeeper.ClientCnxn - Opening socket connection to server /192.168.0.138:2181
2013-01-16 15:26:13:INFO org.apache.zookeeper.ClientCnxn - Socket connection established to 192.168.0.138/192.168.0.138:2181, initiating session
2013-01-16 15:26:13:INFO org.apache.zookeeper.ClientCnxn - Session establishment complete on server 192.168.0.138/192.168.0.138:2181, sessionid = 0x13c3c5224cc0003, negotiated timeout = 4000
2013-01-16 15:26:13:DEBUG com.zoo.demo.ZooKeeperOperator - 獲取設定的資訊：ZooKeeper的Java API測試
節點孩子資訊:
2013-01-16 15:26:13:DEBUG com.zoo.demo.ZooKeeperOperator - /root中存在節點
2013-01-16 15:26:13:DEBUG com.zoo.demo.ZooKeeperOperator - 節點為：child1
2013-01-16 15:26:13:DEBUG com.zoo.demo.ZooKeeperOperator - 節點為：child3
2013-01-16 15:26:13:DEBUG com.zoo.demo.ZooKeeperOperator - 節點為：child2
2013-01-16 15:26:13:INFO org.apache.zookeeper.ZooKeeper - Session: 0x13c3c5224cc0003 closed
2013-01-16 15:26:13:INFO org.apache.zookeeper.ClientCnxn - EventThread shut down
針對出現的中文亂碼看採用下面的處理即可：
String zktest="ZooKeeper的Java API測試";
zkoperator.create("/root/child5", zktest.getBytes("utf-8"));
log.debug("獲取設定的資訊："+new String(zkoperator.getData("/root/child5"),"utf-8"));