ZooKeeper-java client access-getting started

In the previous article, we briefly introduced ZooKeeper deployment and node management.

This section describes how to manage nodes through the java client.

I don't want to introduce them one by one. I believe you can understand them from the comments of the Code.

First, create a basic class for zookeeper, which contains the basic node management methods, as follows:

Package com. zktest. newtest; import java. io. IOException; import java. util. list; import java. util. concurrent. countDownLatch; import org. apache. zookeeper. createMode; import org. apache. zookeeper. keeperException; 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; import org. apache. zookeeper. data. stat; public class BaseZookeeper implements Watcher {public ZooKeeper zooKeeper; private static final int SESSION_TIME_OUT = 2000; private CountDownLatch countDownLatch = new CountDownLatch (1 ); /*** connect zookeeper ** @ param host * @ throws IOException * @ throws handle */public void connectZookeeper (String host) throws IOException, InterruptedException {zooKeeper = new ZooKeeper (host, SESSION_TIME_OUT, this); countDownLatch. await (); System. out. println ("zookeeper connect OK");}/*** implements the watcher interface method. After the connection to zookeeper is successful, zookeeper notifies watcher through this method.
* If a successful connection event is received, countDown the thread to continue other tasks. * // @ Overridepublic void process (WatchedEvent event) {if (event. getState () = KeeperState. syncConnected) {System. out. println ("watcher received event"); countDownLatch. countDown () ;}}/*** create a node based on the path, and set the node data * @ param path * @ param data * @ return * @ throws KeeperException * @ throws InterruptedException */public String createNode (String path, byte [] data) throws KeeperException, interruptedException {return this. zooKeeper. create (path, data, Ids. OPEN_ACL_UNSAFE, CreateMode. PERSISTENT);}/*** obtain all child nodes by path ** @ param path * @ return * @ throws KeeperException * @ throws InterruptedException */public List
 
  
GetChildren (String path) throws KeeperException, InterruptedException {return this. zooKeeper. getChildren (path, false);} public Stat setData (String path, byte [] data, int version) throws KeeperException, InterruptedException {return this. zooKeeper. setData (path, data, version );} /*** obtain node data by path ** @ param path * @ return * @ throws KeeperException * @ throws InterruptedException */public byte [] getData (Str Ing path) throws KeeperException, InterruptedException {return this. zooKeeper. getData (path, false, null );} /*** delete a node ** @ param path * @ param version * @ throws InterruptedException * @ throws KeeperException */public void deletNode (String path, int version) throws InterruptedException, keeperException {this. zooKeeper. delete (path, version);}/*** close the zookeeper connection ** @ throws InterruptedException */public v Oid closeConnect () throws InterruptedException {if (null! = ZooKeeper) {zooKeeper. close ();}}}
 

Create a client for testing. The Code is as follows:

Package com. spg. zktest. newtest; import java. io. IOException; import java. util. arrays; import java. util. list; import org. apache. zookeeper. keeperException; public class Client {/*** @ param args * @ throws InterruptedException * @ throws IOException * @ throws KeeperException */public static void main (String [] args) throws IOException, interruptedException, KeeperException {BaseZookeeper baseZookeeper = new BaseZookeeper (); String host = "192.168.183.128: 2181"; // connect zookeeperbaseZookeeper. connectZookeeper (host); System. out. println ("-------- connect zookeeper OK -----------"); // create a node byte [] data = {1, 2, 3, 4, 5}; String result = baseZookeeper. createNode ("/test", data); System. out. println (result); System. out. println ("-------- create node OK -----------"); // obtain the List of all nodes in a path
 
  
Children = baseZookeeper. getChildren ("/"); for (String child: children) {System. out. println (child);} System. out. println ("-------- get children OK -----------"); // obtain node Data byte [] nodeData = baseZookeeper. getData ("/test"); System. out. println (Arrays. toString (nodeData); System. out. println ("-------- get node data OK -----------"); // update node data = "test data ". getBytes (); baseZookeeper. setData ("/test", data, 0); System. out. println ("-------- set node data OK -----------"); nodeData = baseZookeeper. getData ("/test"); System. out. println (Arrays. toString (nodeData); System. out. println ("-------- get node new data OK -----------"); baseZookeeper. closeConnect (); System. out. println ("-------- close zookeeper OK -----------");}}
 

The result is as follows:

1: nodes under the root directory

2: view the test node Information

OK. The test result ends here.