ZooKeeper編程02--多線程的分佈式鎖

面向過程版：

package distributedLockProcess;

import java.util.Collections;
import java.util.List;
import java.util.concurrent.CountDownLatch;

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.data.Stat;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.ZooKeeper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class dl {
	private static final Logger LOG = LoggerFactory.getLogger(dl.class);

	//確保所有線程運行結束；
	private static final String CONNECTION_STRING = "192.168.1.201:2181,192.168.1.202:2181,192.168.1.203:2181";
	private static final int SESSION_TIMEOUT = 10000;
	private static final String GROUP_PATH = "/disLocks";
	private static final String SUB_PATH = "/disLocks/sub";
	
	private static final int THREAD_NUM = 10; 
	public static CountDownLatch threadSemaphore = new CountDownLatch(THREAD_NUM);

	public static void main(String[] args) {
	        for(int i=0; i < THREAD_NUM; i++){
	            final int threadId = i;
	            new Thread(){
	                @Override
	                public void run() {
	                	final CountDownLatch countDownLatch = new CountDownLatch(1);
	                    try{
	                    	//此線程連接ZooKeeper
	                    	ZooKeeper zk = new ZooKeeper(CONNECTION_STRING, SESSION_TIMEOUT, new Watcher(){
	                    		@Override
	                    		public void process(WatchedEvent event){
	                    			if (event.getState() == KeeperState.SyncConnected){
	                    				countDownLatch.countDown();
	                    			}
	                    		}
	                    	});
	                		countDownLatch.await();
	                		System.out.println(Thread.currentThread().getName() + " --- ZooKeeper.connect()");
	                       			
                			//GROUP_PATH不存在的話，由一個線程創建即可；
                			if(zk.exists(GROUP_PATH, false)==null){
                	            LOG.info( Thread.currentThread().getName() + "節點創建成功, Path: "
                	                    + zk.create( GROUP_PATH,
                	                    ("該節點由線程"+Thread.currentThread().getName() + "創建").getBytes(),
                	                    ZooDefs.Ids.OPEN_ACL_UNSAFE,
                	                    CreateMode.PERSISTENT )
                	                    + ", content: " + ("該節點由線程"+Thread.currentThread().getName() + "創建") );
                	        }
                	      
                			String selfPath = zk.create(SUB_PATH,null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);
                		    LOG.info(Thread.currentThread().getName()+"創建鎖路徑:"+selfPath);
                		    if(checkMinPath(zk, selfPath)){
                		    	LOG.info(Thread.currentThread().getName() + "獲取鎖成功，趕緊幹活！");
                		    	dosomething();
                			    threadSemaphore.countDown();
                		    	try {
                            		if(zk.exists(selfPath,false) == null){
                            			LOG.error(Thread.currentThread().getName()+"本節點已不在了...");
                            			return;
                            		}
                            		zk.delete(selfPath, -1);
                            		LOG.info(Thread.currentThread().getName() + "刪除本節點："+selfPath);
                            		zk.close();
                          		} catch (InterruptedException e) {
                          			// TODO Auto-generated catch block
                          			e.printStackTrace();
                          		} catch (KeeperException e) {
                          			// TODO Auto-generated catch block
                          			e.printStackTrace();
                          		}
                		        }
                		        	                                    			
	                    } catch (Exception e){
	                        LOG.error("【第"+threadId+"個線程】 拋出的異常：");
	                        e.printStackTrace();
	                    }
	                }
	            }.start();
	        }
	        try {
//	        	Thread.sleep(60000);
	        	threadSemaphore.await();
	            LOG.info("所有線程運行結束!");
	        } catch (Exception e) {
	            e.printStackTrace();
	        }
	    }

	protected static boolean checkMinPath(final ZooKeeper zk, final String selfPath) throws KeeperException, InterruptedException {
		List<String> subNodes = zk.getChildren(GROUP_PATH, false);
        Collections.sort(subNodes);
        int index = subNodes.indexOf( selfPath.substring(GROUP_PATH.length()+1));
        switch (index){
            case -1:{
                LOG.error(Thread.currentThread().getName()+"本節點已不在了..."+selfPath);
                return false;
            }
            case 0:{
                LOG.info(Thread.currentThread().getName()+"子節點中，我果然是老大"+selfPath);
                return true;
            }
            default:{
                final String waitPath = GROUP_PATH +"/"+ subNodes.get(index - 1);
                LOG.info(Thread.currentThread().getName()+"獲取子節點中，排在我前面的"+waitPath);
                try{
                    zk.getData(waitPath, new Watcher(){
                    	@Override
                    	public void process(WatchedEvent event) {
                    		if (event.getType() == Event.EventType.NodeDeleted && event.getPath().equals(waitPath)) {  
                                LOG.info(Thread.currentThread().getName()+ "收到情報，排我前面的傢伙已掛，我是不是可以出山了？");  
                                try {  
                                    if(checkMinPath(zk, selfPath)){  
                                    	LOG.info(Thread.currentThread().getName() + "獲取鎖成功，趕緊幹活！");
                                	    dosomething();
                                	    threadSemaphore.countDown();
                                    	
                                    	try {
                                    		if(zk.exists(selfPath,false) == null){
                                    			LOG.error(Thread.currentThread().getName()+"本節點已不在了...");
                                    		} else {
                                    			zk.delete(selfPath, -1);
                                    			LOG.info(Thread.currentThread().getName() + "刪除本節點："+selfPath);
                                    			zk.close();                                    			
                                    		}
	                              		} catch (InterruptedException e) {
	                              			// TODO Auto-generated catch block
	                              			e.printStackTrace();
	                              		} catch (KeeperException e) {
	                              			// TODO Auto-generated catch block
	                              			e.printStackTrace();
	                              		}
                                    }  
                                } catch ( Exception e) {  
                                    e.printStackTrace();  
                                }  
                            } 
                    	}
                    }, new Stat());
         
                }catch(KeeperException e){
                    if(zk.exists(waitPath,false) == null){
                        LOG.info(Thread.currentThread().getName()+"子節點中，排在我前面的"+waitPath+"已失蹤，幸福來得太突然?");
                        return checkMinPath(zk, selfPath);
                    }else{
                        throw e;
                    }
                } catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
            }
        }
		return false;
	}

	protected static void dosomething() {
		System.out.println("我正在獨享資源互斥地進行工作。。。");
	}
}

面向對象重構版：

package distributedLockObject;
import java.io.IOException;
import java.util.concurrent.CountDownLatch;

import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.KeeperState;
import org.apache.zookeeper.ZooKeeper;


public class AbstractZooKeeper implements Watcher{
	protected ZooKeeper zookeeper;
	protected CountDownLatch countDownLatch = new CountDownLatch(1);
	
	public ZooKeeper connect(String hosts, int SESSION_TIMEOUT) throws IOException, InterruptedException{
		zookeeper = new ZooKeeper(hosts, SESSION_TIMEOUT, this);
		countDownLatch.await();
		System.out.println("AbstractZooKeeper.connect()");
		return zookeeper;
	}
	
	public void process(WatchedEvent event){
		if (event.getState() == KeeperState.SyncConnected){
			countDownLatch.countDown();
		}
	}
	
	public void close() throws InterruptedException{
		zookeeper.close();
	}
}

package distributedLockObject;

import java.util.Collections;
import java.util.List;

import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class DistributedLock    {
    private ZooKeeper zk = null;
    private String selfPath;
    private String waitPath;
    private String LOG_PREFIX_OF_THREAD=Thread.currentThread().getName();
    private static final String GROUP_PATH = "/disLocks";
    private static final String SUB_PATH = "/disLocks/sub";
    
    private static final Logger LOG = LoggerFactory.getLogger(DistributedLock.class);
    
    private Watcher  watcher;
    public DistributedLock(ZooKeeper  zk ) {
      
      this.zk = zk; 
    }
    
    
    
    public Watcher getWatcher() {
		return watcher;
	}



	public void setWatcher(Watcher watcher) {
		this.watcher = watcher;
	}



	/**
     * 獲取鎖
     * @return
     */
    public boolean  getLock()  throws KeeperException, InterruptedException {
        selfPath = zk.create(SUB_PATH,null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);
        LOG.info(LOG_PREFIX_OF_THREAD+"創建鎖路徑:"+selfPath);
        if(checkMinPath()){
           return true;
        }
        
        return false;
    }
    /**
     * 創建節點
     * @param path 節點path
     * @param data 初始數據內容
     * @return
     */
    public boolean createPath( String path, String data  ) throws KeeperException, InterruptedException {
        if(zk.exists(path, false)==null){
            LOG.info( LOG_PREFIX_OF_THREAD + "節點創建成功, Path: "
                    + this.zk.create( path,
                    data.getBytes(),
                    ZooDefs.Ids.OPEN_ACL_UNSAFE,
                    CreateMode.PERSISTENT )
                    + ", content: " + data );
        }
        return true;
    }
 
      
    
 
    
    public void unlock(){
    	 try {
    		  if(zk.exists(this.selfPath,false) == null){
    	            LOG.error(LOG_PREFIX_OF_THREAD+"本節點已不在了...");
    	            return;
    	        }
			 zk.delete(this.selfPath, -1);
			 LOG.info(LOG_PREFIX_OF_THREAD + "刪除本節點："+selfPath);
	         zk.close();
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (KeeperException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
    	
    }
    
 
    /**
     * 檢查自己是不是最小的節點
     * @return
     */
    public  boolean checkMinPath() throws KeeperException, InterruptedException {
         List<String> subNodes = zk.getChildren(GROUP_PATH, false);
         Collections.sort(subNodes);
         int index = subNodes.indexOf( selfPath.substring(GROUP_PATH.length()+1));
         switch (index){
             case -1:{
                 LOG.error(LOG_PREFIX_OF_THREAD+"本節點已不在了..."+selfPath);
                 return false;
             }
             case 0:{
                 LOG.info(LOG_PREFIX_OF_THREAD+"子節點中，我果然是老大"+selfPath);
                 return true;
             }
             default:{
                 this.waitPath = GROUP_PATH +"/"+ subNodes.get(index - 1);
                 LOG.info(LOG_PREFIX_OF_THREAD+"獲取子節點中，排在我前面的"+waitPath);
                 try{
                     zk.getData(waitPath, this.watcher, new Stat());
                     return false;
                 }catch(KeeperException e){
                     if(zk.exists(waitPath,false) == null){
                         LOG.info(LOG_PREFIX_OF_THREAD+"子節點中，排在我前面的"+waitPath+"已失蹤，幸福來得太突然?");
                         return checkMinPath();
                     }else{
                         throw e;
                     }
                 }
             }
         }
     
    }

	public String getWaitPath() {
		return waitPath;
	}
 
    
   
}

package distributedLockObject;

public interface DoTemplate {
	void dodo();
}

package distributedLockObject;

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

import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.ZooKeeper;


public class LockService {

	 //確保所有線程運行結束；
	private static final String CONNECTION_STRING = "192.168.1.201:2181,192.168.1.202:2181,192.168.1.203:2181";
	private static final int THREAD_NUM = 10; 
	public static   CountDownLatch threadSemaphore = new CountDownLatch(THREAD_NUM);
	private static final String GROUP_PATH = "/disLocks";

	private static final int SESSION_TIMEOUT = 10000;
	AbstractZooKeeper az = new AbstractZooKeeper();
	
	
	public void doService(DoTemplate doTemplate){
		try {
			ZooKeeper zk = az.connect(CONNECTION_STRING,SESSION_TIMEOUT);
			DistributedLock dc = new DistributedLock(zk);
			LockWatcher lw = new LockWatcher(dc,doTemplate);
			dc.setWatcher(lw);
			//GROUP_PATH不存在的話，由一個線程創建即可；
			dc.createPath(GROUP_PATH, "該節點由線程"+Thread.currentThread().getName() + "創建");
			boolean rs = dc.getLock();
			if (rs==true) {
				lw.dosomething();
				dc.unlock();
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (KeeperException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

package distributedLockObject;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class LockWatcher implements Watcher{
	private static final Logger LOG = LoggerFactory.getLogger(LockWatcher.class);

	private DistributedLock distributedLock;
	private  DoTemplate doTemplate;
	public LockWatcher(DistributedLock distributedLock,DoTemplate doTemplate) {
		// TODO Auto-generated constructor stub
		this.distributedLock = distributedLock;
		this.doTemplate = doTemplate;
	}
	
	
	@Override
	public void process(WatchedEvent event) {
		// TODO Auto-generated method stub
		if (event.getType() == Event.EventType.NodeDeleted && event.getPath().equals(distributedLock.getWaitPath())) {  
            LOG.info(Thread.currentThread().getName()+ "收到情報，排我前面的傢伙已掛，我是不是可以出山了？");  
            try {  
                if(distributedLock.checkMinPath()){  
                	dosomething();
                	distributedLock.unlock();
                }  
            } catch ( Exception e) {  
                e.printStackTrace();  
            }  
        } 
	}
	
	public   void dosomething(){
	    LOG.info(Thread.currentThread().getName() + "獲取鎖成功，趕緊幹活！");
	    doTemplate.dodo();
	    TestLock.threadSemaphore.countDown();
	    
	    
	}

}

package distributedLockObject;
import java.util.concurrent.CountDownLatch;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class TestLock {
	private static final Logger LOG = LoggerFactory.getLogger(TestLock.class);
	 //確保所有線程運行結束；

	private static final int THREAD_NUM = 10; 
	public static   CountDownLatch threadSemaphore = new CountDownLatch(THREAD_NUM);

	public static void main(String[] args) {
	        for(int i=0; i < THREAD_NUM; i++){
	            final int threadId = i;
	            new Thread(){
	                @Override
	                public void run() {
	                    try{
	                    	 new LockService().doService(new DoTemplate() {
								
								@Override
								public void dodo() {
									// TODO Auto-generated method stub
									LOG.info("我要修改一個文件。。。。"+threadId);
								}
							});
	                    } catch (Exception e){
	                        LOG.error("【第"+threadId+"個線程】 拋出的異常：");
	                        e.printStackTrace();
	                    }
	                }
	            }.start();
	        }
	        try {
//	        	Thread.sleep(60000);
	        	threadSemaphore.await();
	            LOG.info("所有線程運行結束!");
	        } catch (Exception e) {
	            e.printStackTrace();
	        }
	    }
}