Zookeeper-api基础教程

第一关、创建会话与关闭

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import java.io.IOException;
import org.apache.zookeeper.WatchedEvent;  
import org.apache.zookeeper.Watcher;  
import org.apache.zookeeper.ZooKeeper;
public class test1 {
    // 初始化 ZooKeeper 实例  
    private ZooKeeper zk;  
    // 实现一个 Watcher  
    // 请在此处编写代码  
    /********* Begin *********/  
    private Watcher wh = new Watcher() {  
        // 重写 process 方法  
        public void process(WatchedEvent event) {  
            System.out.println(event);  
        }  
    };  
    /********* End *********/
    // 连接 ZooKeeper 服务器  
    private void createZKInstance() throws IOException {  
        // 请在此处编写代码  
        /********* Begin *********/  
        zk = new ZooKeeper("localhost:2181", 15000, this.wh);  
        /********* End *********/
    }
    // 断开连接  
    private void ZKClose() throws InterruptedException {  
        // 请在此处编写代码  
        /********* Begin *********/  
        zk.close();  
        /********* End *********/  
    }
    public static void main(String[] args) throws IOException, InterruptedException{  
        test1 test = new test1();  
        //  连接 ZooKeeper 服务器  
        test.createZKInstance();  
        // 断开连接  
        test.ZKClose();  
    }  
}

第二关、节点删除与创建

import org.apache.zookeeper.*;
import java.io.IOException;
public class Student {  
    // 初始化 ZooKeeper 实例  
    private ZooKeeper zk;  
    // 实现一个 Watcher  
    private Watcher wh = new Watcher() {  
        // 重写 process 方法  
        public void process(WatchedEvent event) {  
            System.out.println(event);  
        }  
    };
    // 连接ZooKeeper服务器  
    public ZooKeeper createZKInstance() throws IOException {          
        zk = new ZooKeeper("localhost:2181", 15000, this.wh);  
        return zk;  
    }
   // 使用同步方式删除节点 /mynode1  
   public void deleteNode() throws KeeperException, InterruptedException {  
       // 请在此处编写代码  
        /********* Begin *********/  
        zk.delete("/mynode1",-1);  
        /********* End *********/
    }  
    // 使用异步方式创建节点 /mynode1  
    public void createNodeSync() {  
        // 请在此处编写代码  
        /********* Begin *********/  
        String path = "/mynode1";  
        zk.create(path, "This node is mine!".getBytes(), ZooDefs.Ids.READ_ACL_UNSAFE, CreateMode.PERSISTENT,new test.MyStringCallback(),"CreateMynode!" );  
        /********* End *********/
   }
}

第三关、节点数据获取

import org.apache.zookeeper.*;  
import org.apache.zookeeper.data.Stat;
import java.io.IOException;
public class Student {  
    // 初始化 ZooKeeper 实例  
    private ZooKeeper zk;  
    // 实现一个 Watcher  
    private Watcher wh = new Watcher() {  
        // 重写 process 方法  
        public void process(WatchedEvent event) {  
            System.out.println(event);  
        }  
    };  
    // 连接ZooKeeper服务器  
    public ZooKeeper createZKInstance() throws IOException {  
        zk = new ZooKeeper("localhost:2181", 15000, this.wh);  
        return zk;  
    }
    // 同步获取节点数据  
    public  void getData() throws IOException, KeeperException, InterruptedException {  
        // 请在此处编写代码  
        /********* Begin *********/  
        Stat stat = new Stat();  
        byte[] data = zk.getData("/myzk", wh, stat);  
        System.out.println(new String(data));  
        /********* End *********/
    }
}

第四关、异步回调

import org.apache.zookeeper.*;  
import org.apache.zookeeper.data.Stat;
import java.io.IOException;
public class Student {  
    // 初始化 ZooKeeper 实例  
    private ZooKeeper zk;  
    // 实现一个 Watcher  
    private Watcher wh = new Watcher() {  
        // 重写 process 方法  
        public void process(WatchedEvent event) {  
            System.out.println(event);  
        }  
    };  
    // 连接ZooKeeper服务器  
    public ZooKeeper createZKInstance() throws IOException {  
        zk = new ZooKeeper("localhost:2181", 15000, this.wh);  
        return zk;  
    }
    // 异步删除节点  
    public  void deleteNode() throws IOException, KeeperException, InterruptedException {  
        // 请在此处编写代码  
        /********* Begin *********/  
        Stat stat = new Stat();  
        zk.delete("/mycallnode",stat.getVersion(),new MyCallback(),"delete");  
        /********* End *********/
    }  
    // 请在此处编写代码，完成回调函数的编写  
    /********* Begin *********/      
    public static class MyCallback  implements AsyncCallback.VoidCallback{  
        // 重写 processResult 方法  
        @Override  
        public void processResult(int i, String s, Object o) {  
            // 输出上下文信息  
            System.out.println(o);  
        }  
    }  
    /********* End *********/
}