Zookeeper入门开发demo

package CreateGroup;

import java.io.IOException;
import java.util.List;
import java.util.concurrent.CountDownLatch;

import org.apache.zookeeper.AsyncCallback;
import org.apache.zookeeper.AsyncCallback.Children2Callback;
import org.apache.zookeeper.AsyncCallback.ChildrenCallback;
import org.apache.zookeeper.AsyncCallback.StatCallback;
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;
import org.apache.zookeeper.server.ConnectionBean;


public class TestZkGroup implements Watcher {
	private static final int SESSION_TIMEOUT = 5000;
	
	private ZooKeeper zk;
	private CountDownLatch connectedSignal = new CountDownLatch(2);
	Childwatcher childwatcher = new Childwatcher(); 
	
	private void getthreadname(String funname){
		Thread current = Thread.currentThread();  
		System.out.println(funname + " is call in  " + current.getName());
	}
	
	@Override
	// 运行在另外一个线程 main-EventThread
	public void process(WatchedEvent event) {
		getthreadname("process");
		System.out.println((event.getType()));  // 打印状态
		
		if (event.getState() == KeeperState.SyncConnected){
			connectedSignal.countDown();
		}
	}
	
	// 测试自定义监听
	public Watcher wh = new Watcher() {
		public void process(WatchedEvent event) {
			getthreadname("Watcher::process");
			System.out.println("回调watcher实例： 路径" + event.getPath() + " 类型："
			+ event.getType());
		}
	};
	
	public void connect(String hosts) throws IOException, InterruptedException{
		getthreadname("connect");
		zk = new ZooKeeper(hosts, SESSION_TIMEOUT, wh); // 最后一个参数用this会调用自身的监听  wh 代表？
		//connectedSignal.await(); // 主线程挂起
	}
	
	// 加入组(可以理解成一个创建本次连接的一个组)
	public void join(String groupname, String meberName) throws KeeperException, InterruptedException{
		 String path = "/" + groupname + "/" + meberName ;
        
        
		// EPHEMERAL断开将被删除
		String createdpath = zk.create(path, null, Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);
		System.out.println("join : " + createdpath);
	}
	
    public List<String> getChilds(String path) throws KeeperException, InterruptedException {  
        // TODO Auto-generated method stub  
        if (zk != null) {  
            // return zk.getChildren(path, false); // false表示没有设置观察 
        	//zk.getChildren(path, true, childwatcher.processResult, null);
        	zk.getChildren( path, true, new AsyncCallback.Children2Callback() {
				@Override
				public void processResult(int rc, String path, Object ctx,
						List<String> children, Stat stat) { // stat参数代表元数据
					// TODO Auto-generated method stub
					System.out.println("****");
				  	for (int i = 0; i < children.size() - 1; i ++){
		        		System.out.println("mempath = " + children.get(i) + stat);
		        	}	
				}
    }, null);
        	
        }  
        return null;  
    }  
	
	public void create(String path) throws KeeperException, InterruptedException, IOException{
		// Ids.OPEN_ACL_UNSAFE 开放式ACL，允许任何客户端对znode进行读写
		// CreateMode.PERSISTENT 持久的znode，本次连接断开后还会存在，应该有持久化操作.
		// PERSISTENT_SEQUENTIAL 持久化顺序，这个由zookeeper来保证
		
		String createdpath = zk.create(path, null, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
		System.out.println("crateed : " + createdpath);    
	}
	
	private void close() throws InterruptedException{
		if  (zk != null){
			zk.close();
		}
	}
	
	public static class Childwatcher implements Children2Callback{
		public ChildrenCallback processResult;

		@Override
		public void processResult(int rc, String path, Object ctx,
				List<String> children, Stat stat) {
			// TODO Auto-generated method stub
			System.out.println("**** path " + stat);
		}
	}
	
	public void delete(String groupname) throws InterruptedException, KeeperException{		
		zk.delete(groupname, -1);
	}
	
	public Stat isexist(String groupname) throws InterruptedException, KeeperException{		
		return zk.exists(groupname, true); // this
	}
	
	 public void write(String path, String value)throws Exception{  
         Stat stat=zk.exists(path, false);  
         if(stat==null){  
             zk.create(path, value.getBytes("UTF-8"), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);  
         }else{  
               
             zk.setData(path, value.getBytes("UTF-8"), -1);  
         }      
     }  
	 
	 public String read(String path,Watcher watch)throws Exception{  
         byte[] data=zk.getData(path, watch, null);             
         return new String(data, "UTF-8");  
     }  

	public static void main(String[] args) throws Exception {	
		String hosts = "localhost";
		String groupname = "zktest" ;
		String meberName = String.valueOf(System.currentTimeMillis());
		String path = "/" + groupname;
		
		// create
		TestZkGroup test = new TestZkGroup();
		//  连接
		test.connect(hosts);
		// 
	    if (null != test.isexist(path)){
	    	test.delete(path);
	    }
		
		test.isexist(path);
        test.create(path);
        
        test.isexist(path);
        test.write(path, "test");
        
        test.isexist(path);
        String result = test.read(path, test.wh);
        System.out.println(path + " value = " + result);
        
        int sum = 0;
        for (int j = 0 ; j< 10000; j++){
        	sum++;
        	Thread.sleep(10);
        }
        System.out.println(sum);
        test.close();
   
      System.exit(2);
		// 一个本地连接的znode
		test.connect(hosts);
        test.join(groupname, meberName);
        
        // 遍历
        List<String> memlist = test.getChilds("/" + "zktest" );
        if (memlist != null){
        	for (int i = 0; i < memlist.size() - 1; i ++){
        		System.out.println("mempath = " + memlist.get(i));
        	}
        }
	}
}