Relying on zookeeper to generate globally unique serial numbers

Below 2 images from: http://www.open-open.com/doc/view/2e0a82e0081d489dace301a2c512053c

For zookeeper service installation, configuration, startup, client operations see:

http://aiilive.blog.51cto.com/1925756/1684451

http://aiilive.blog.51cto.com/1925756/1684145

1. Generate serial numbers using Zookeeper's Znode data version

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Using the Zkclient Encapsulation package operation:

Create a "/CREATESEQ" node that stores the SEQ in advance  createmode.persistentpublic static final string seq_znode  =  "/SEQ"//Distributed SEQ generation via Znode data version public static class task1 implements  runnable {    private final string taskname;     Public task1 (String taskname)  {        this.taskname  = taskName;    }     @Override     public  void run ()  {        zkclient zkclient =  new zkclient ("192.168.88.153:2181",  3000, 1000);         stat stat = zkclient.writedata (seq_znode, new byte[0], -1);         int versionasseq = stat.getversion ();         syStem.out.println (taskname +  " obtain seq="  + versionasseq);         zkclient.close ();     }}//mainfinal executorservice  service = executors.newfixedthreadpool (;for ) (int i = 0; i  < 20; i++)  {    service.execute (New task1 ("[Concurrent-"  +  i +  "]));}

2. Implementation of Znode and distributed lock persistence Znode with temporary serial number

2.1 is implemented by using distributed lock persistence Znode

The client uses the Apache curator framework, code: HTTPS://CODE.CSDN.NET/SNIPPETS/929300

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2.2 Znode with a temporary serial number

Client use: Zkclient (https://github.com/adyliu/zkclient)

Create the node "/lock" of the lock object in advance createmode.persistentpublic static final String Lock_znode = "/lock";

Distributed-type lock for generating public static class task2 implements runnable, izkchildlistener of distributive seq  {    private final string taskname;    private  final zkclient zkclient;    private final string lockprefix  =  "/loc";    private final string selfznode;     public task2 (String taskname)  {         This.taskname = taskname;        zkclient = new  zkclient ("192.168.88.153:2181",  30000, 10000);         Selfznode = zkclient.createephemeralsequential (lock_znode + lockprefix, new byte [0]);     }     @Override     public void run ()  {        zkclient.subscribechildchanges (lock_znode, this);         do {        } while  ( Zkclient.isconnected ());     }    private void createseq ()  {        stat stat = new stat ();         byte[] olddata = zkclient.readdata (LOCK_ZNODE, stat);         byte[] newdata = update (OldData);         zkclient.writedata (Lock_znode, newdata);         system.out.println (taskname + selfznode +  " obtain seq="  + new string (NewData));     }    private byte[]  update (Byte[] currentdata)  {        string s = new string (CurrentData) ;         int d = integer.parseint (s);         d = d + 1;        s  = string.valueof (d);         return s.getbytes ();     }     @Override     public void  Handlechildchange (String parentpath, list<string> currentchildren)  throws  exception {        string[] childrensznode =  Currentchildren.toarray (New string[currentchildren.size ());         arrays.sort (Childrensznode);         string minznode =  LOCK_ZNODE +  "/"  + childrensznode[0];        if  (SelfZnode.equals (MinZnode))  {            createseq ();             zkclient.unsubscribechildchanges (LOCK_ZNODE, this);             zkclient.delete (SelfZnode);             zkclient.close ();         }    }}

Complete code See: https://code.csdn.net/snippets/929320

This article is from the "Red Horse Red" blog, please be sure to keep this source http://aiilive.blog.51cto.com/1925756/1685614

Relying on zookeeper to generate globally unique serial numbers