ZooKeeper (iv)--use of third-party client Zkclient

Objective

Zkclient has done two main things:

One is to automatically create a new zookeeper instance to re-connect when the session loss and session expire.

The other is to wrap the disposable watcher as a durable watcher. The latter is done simply by re-reading the data and then registering the same watcher instance in the watcher callback.

Zkclient has been used in a number of projects, well-known Dubbo, Kafka, Helix.

Zkclient jar Package Download, or add maven dependencies directly: Http://mvnrepository.com/artifact/com.101tec/zkclient

Maven dependencies:

<!--https://mvnrepository.com/artifact/com.101tec/zkclient -<Dependency>    <groupId>Com.101tec</groupId>    <Artifactid>Zkclient</Artifactid>    <version>0.10</version></Dependency>

Body

1. Test class

Package Com.xbq.demo;import java.io.ioexception;import org. i0itec.zkclient.zkclient;import org. i0itec.zkclient.izkdatalistener;/** * @ClassName: Zkclientdemo * @Description: TODO (zkclient test) * @author XBQ * @date 2017-3-26 a.m. 11:49:39 */public class Zkclientdemo {//This demo uses a cluster, so there are multiple IPs and ports private static String Connect_server =    "192.168.99.138:2181,192.168.99.138:2182,192.168.99.138:2183";    private static int session_timeout = 3000;    private static int connection_timeout = 3000;        private static zkclient zkclient;    static {zkclient = new zkclient (Connect_server, Session_timeout,connection_timeout,new Myzkserializer ()); public static void Main (string[] args) {Add (zkclient);//update (zkclient);//delete        (zkclient);        Adddigui (zkclient);//Deletedigui (zkclient);    Subscribe (zkclient); }/** * @Title: Add * @Description: TODO (add a specified node) * @param @param zkclient   Set file * @return void return type * @throws */public static void Add (Zkclient zkclient) {//If no node exists,        Create a new node if (!zkclient.exists ("/config")) {zkclient.createpersistent ("/config", "Javacoder");        }//Check to see if the increase succeeds String value = Zkclient.readdata ("/config");    System.out.println ("value===" + value); }/** * @Title: Addsequential * @Description: TODO (Create node recursively) * @param @param zkclient settings file * @r Eturn void return type * @throws */public static void Adddigui (Zkclient zkclient) {//Recursive create node Zkclie         Nt.createpersistent ("/xbq/java/coder", true); if (zkclient.exists ("/xbq/java/coder")) {System.out.println ("Add success!")        "); }else {System.out.println ("Increase failed!        "); }}/** * @Title: Delete * @Description: TODO (delete specified node) * @param @param zkclient settings file * @ret urn void return type * @throws */public static void Delete (ZKCLIEnt zkclient) {//Presence node is removed if (zkclient.exists ("/config")) {Boolean flag = Zkclient.delete ("/conf            IG "); System.out.println ("delete" + (flag = = true?) Success ":" Failed!        ")); }}/** * @Title: Deletedigui * @Description: TODO (Recursive delete) * @param @param zkclient settings file * @        return void returns type * @throws */public static void Deletedigui (Zkclient zkclient) {//Presence node for deletion The IF (zkclient.exists ("/XBQ")) {/////Recursive delete is only passed to the parent node, and if all nodes are passed in, the return is true, but still not deleted,//Because Zkclient will              The exception is encapsulated, and when it enters the catch, it returns True, which is a pit Boolean flag = zkclient.deleterecursive ("/XBQ"); System.out.println ("delete" + (flag = = true?) Success ":" Failed!        ")); }}/** * @Title: Update * @Description: TODO (Modify the value of the node) * @param @param zkclient settings file * @ret urn void return type * @throws * * public static void update (Zkclient zkclient) {if (Zkclient.exists ("/config          ")){  Zkclient.writedata ("/config", "testupdate");            Check to see if the modification succeeds String value = Zkclient.readdata ("/config");        System.out.println ("value===" + value); }}/** * @Title: Subscribe * @Description: TODO (Event subscription, can be used for configuration management) * Subscribe first, then operate the add and revise. (Can subscribe multiple clients) * @param @param zkclient settings file * @return void return type * @throws */public static void S Ubscribe (zkclient zkclient) {zkclient.subscribedatachanges ("/config/username", new Izkdatalistener () {@ Override public void handledatadeleted (String arg0) throws Exception {System.out.println ("triggered delete            Event: "+ arg0);                } @Override public void Handledatachange (String arg0, Object arg1) throws Exception {            System.out.println ("Triggered a Change event:" + arg0 + "-" + arg1);                }        });        try {System.in.read (); } catch (IOException e) {e.printsTacktrace (); }    }}

2. Custom Serialization Classes

Package Com.xbq.demo;import org. i0itec.zkclient.exception.zkmarshallingerror;import org. I0itec.zkclient.serialize.zkserializer;import java.io.unsupportedencodingexception;/** * @ClassName: Myzkserializer  * @Description: TODO (Implement serialization interface, convert to UTF-8 encoding)  * @author XBQ  * @date 2017-3-26 a.m. 11:56:22 */  public class Myzkserializer implements zkserializer{    @Override public    byte[] Serialize (Object data) throws Zkmarshallingerror {        try {            return string.valueof (data). GetBytes ("UTF-8");        } catch ( Unsupportedencodingexception e) {            e.printstacktrace ();        }        return null;    }    @Override Public    Object deserialize (byte[] bytes) throws Zkmarshallingerror {        try {            return new String ( Bytes, "UTF-8");        } catch (Unsupportedencodingexception e) {            e.printstacktrace ();        }        return null;}    }

ZooKeeper (iv)--use of third-party client Zkclient