zookeeper-server-client 简单例子

客户端将初始值加1，然后写入server。
2个客户端输出的值的顺序是一致的。 说明客户端可已感知其他客户端的处理结果。


github 地址
https://github.com/noobthinker/zookeeper-simple-demo

贴代码区域

server

public class Server {

    NIOServerCnxnFactory serverCnxnFactory;

    public void zkStart(Conf conf) throws IOException, InterruptedException {
        ZooKeeperServer zkServer = new ZooKeeperServer();
        File dataDirectory = new File(conf.DIR);
        FileTxnSnapLog ftxn = new FileTxnSnapLog(dataDirectory, dataDirectory);
        zkServer.setTxnLogFactory(ftxn);
        zkServer.setTickTime(conf.TICK_TIME);
        serverCnxnFactory = new NIOServerCnxnFactory();
        serverCnxnFactory.configure(new InetSocketAddress(conf.PORT), conf.MAX_CLIENT_CONNECTIONS);
        serverCnxnFactory.startup(zkServer);
    }
}

client

public class Client implements Watcher, AsyncCallback.StatCallback {

    ZooKeeper zk;
    boolean dead;
    String znode;
    Stat stat;
    int index;

    public void initZkClient(String ipport,int timetout,String znode) {
        try {
            this.znode = znode;
            zk = new ZooKeeper(ipport, timetout, this);
            stat = zk.exists(znode, false);
            if(null == stat){
                zk.create(znode,new byte[0], ZooDefs.Ids.OPEN_ACL_UNSAFE,
                        CreateMode.PERSISTENT);
            }
            zk.getData(znode,this,stat);
        } catch (IOException e) {
            e.printStackTrace();
        }catch (KeeperException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public void processResult(int rc, String s, Object o, Stat stat) {
        boolean exists;
        switch (rc) {
            case KeeperException.Code.Ok:
                exists = true;
                break;
            case KeeperException.Code.NoNode:
                exists = false;
                break;
            case KeeperException.Code.SessionExpired:
            case KeeperException.Code.NoAuth:
                dead = true;
                return;
            default:
                zk.exists(znode, true, this, null);
                return;
        }

        byte b[] = null;
        if (exists) {
            try {
                b = zk.getData(znode, false, null);
                System.out.println(new String(b));
            } catch (KeeperException e) {
                e.printStackTrace();
            } catch (InterruptedException e) {
                return;
            }
        }
    }

    public void process(WatchedEvent event) {
        String path = event.getPath();
        if (event.getType() == Event.EventType.None) {
            switch (event.getState()) {
                case SyncConnected:
                    break;
                case Expired:
                    dead = true;
                    break;
            }
        } else {
            if (path != null && path.equals(znode)) {
                zk.exists(znode, true, this, null);
            }
        }
    }

    public void dataMaker(int i){
        index=i;
        int max=index+10;
        boolean run=true;
        while(run){
            try {
                zk.setData(znode, ((index++) + "").getBytes(), -1);
                Thread.sleep(50);
                if(index>max){
                    run=false;
                    zk.close();
                }
            } catch (KeeperException e) {
                e.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}

conf

public class Conf {
    public String DIR;
    public int TICK_TIME;
    public int PORT;
    public int MAX_CLIENT_CONNECTIONS;
}

test 类

server

public class ZkServer {
    public static void main(String[]args){
        Conf conf = new Conf();
        conf.DIR="/zookeeper";
        conf.PORT=22801;
        conf.TICK_TIME=2000;
        conf.MAX_CLIENT_CONNECTIONS=60;
        Server srv = new Server();
        try {
            srv.zkStart(conf);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

client1

public class ZkClient1 {
    public static void main(String[]args){
        Client client = new Client();
        client.initZkClient("localhost:22801",3000,"/zka");
        client.dataMaker(0);
    }
}

client1 输出

 0 20 1 21 2 22 3 23 4 24 5 25 6 26 7 27 8 28 9 29 10 30

client2

public class ZkClient2 {
    public static void main(String[]args){
        Client client = new Client();
        client.initZkClient("localhost:22801",3000,"/zka");
        client.dataMaker(20);
    }
}

client2输出

20 1 21 2 22 3 23 4 24 5 25 6 26 7 27 8 28 9 29 10 30

2个端输出一致。