ZooKeeper編程02--多線程的分佈式鎖

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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);//确保所有线程运行结束；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不存在的话，由一个线程创建即可；                if(zk.exists(GROUP_PATH, false)==null){                            LOG.info( Thread.currentThread().getName() + "节点创建成功, Path: "                                    + zk.create( GROUP_PATH,                                    ("该节点由线程"+Thread.currentThread().getName() + "创建").getBytes(),                                    ZooDefs.Ids.OPEN_ACL_UNSAFE,                                    CreateMode.PERSISTENT )                                    + ", content: " + ("该节点由线程"+Thread.currentThread().getName() + "创建") );                        }                                      String selfPath = zk.create(SUB_PATH,null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);                    LOG.info(Thread.currentThread().getName()+"创建锁路径:"+selfPath);                    if(checkMinPath(zk, selfPath)){                    LOG.info(Thread.currentThread().getName() + "获取锁成功，赶紧干活！");                    dosomething();                    threadSemaphore.countDown();                    try {                            if(zk.exists(selfPath,false) == null){                            LOG.error(Thread.currentThread().getName()+"本节点已不在了...");                            return;                            }                            zk.delete(selfPath, -1);                            LOG.info(Thread.currentThread().getName() + "删除本节点："+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+"个线程】 抛出的异常：");                        e.printStackTrace();                    }                }            }.start();        }        try {//        Thread.sleep(60000);        threadSemaphore.await();            LOG.info("所有线程运行结束!");        } 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()+"本节点已不在了..."+selfPath);                return false;            }            case 0:{                LOG.info(Thread.currentThread().getName()+"子节点中，我果然是老大"+selfPath);                return true;            }            default:{                final String waitPath = GROUP_PATH +"/"+ subNodes.get(index - 1);                LOG.info(Thread.currentThread().getName()+"获取子节点中，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()+ "收到情报，排我前面的家伙已挂，我是不是可以出山了？");                                  try {                                      if(checkMinPath(zk, selfPath)){                                      LOG.info(Thread.currentThread().getName() + "获取锁成功，赶紧干活！");                                    dosomething();                                    threadSemaphore.countDown();                                                                        try {                                    if(zk.exists(selfPath,false) == null){                                    LOG.error(Thread.currentThread().getName()+"本节点已不在了...");                                    } else {                                    zk.delete(selfPath, -1);                                    LOG.info(Thread.currentThread().getName() + "删除本节点："+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()+"子节点中，排在我前面的"+waitPath+"已失踪，幸福来得太突然?");                        return checkMinPath(zk, selfPath);                    }else{                        throw e;                    }                } catch (InterruptedException e) {// TODO Auto-generated catch blocke.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;}/**     * 获取锁     * @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+"创建锁路径:"+selfPath);        if(checkMinPath()){           return true;        }                return false;    }    /**     * 创建节点     * @param path 节点path     * @param data 初始数据内容     * @return     */    public boolean createPath( String path, String data  ) throws KeeperException, InterruptedException {        if(zk.exists(path, false)==null){            LOG.info( LOG_PREFIX_OF_THREAD + "节点创建成功, 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+"本节点已不在了...");                return;            } zk.delete(this.selfPath, -1); LOG.info(LOG_PREFIX_OF_THREAD + "删除本节点："+selfPath);         zk.close();} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (KeeperException e) {// TODO Auto-generated catch blocke.printStackTrace();}        }         /**     * 检查自己是不是最小的节点     * @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+"本节点已不在了..."+selfPath);                 return false;             }             case 0:{                 LOG.info(LOG_PREFIX_OF_THREAD+"子节点中，我果然是老大"+selfPath);                 return true;             }             default:{                 this.waitPath = GROUP_PATH +"/"+ subNodes.get(index - 1);                 LOG.info(LOG_PREFIX_OF_THREAD+"获取子节点中，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+"子节点中，排在我前面的"+waitPath+"已失踪，幸福来得太突然?");                         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 { //确保所有线程运行结束；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不存在的话，由一个线程创建即可；dc.createPath(GROUP_PATH, "该节点由线程"+Thread.currentThread().getName() + "创建");boolean rs = dc.getLock();if (rs==true) {lw.dosomething();dc.unlock();}} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (KeeperException e) {// TODO Auto-generated catch blocke.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 stubthis.distributedLock = distributedLock;this.doTemplate = doTemplate;}@Overridepublic void process(WatchedEvent event) {// TODO Auto-generated method stubif (event.getType() == Event.EventType.NodeDeleted && event.getPath().equals(distributedLock.getWaitPath())) {              LOG.info(Thread.currentThread().getName()+ "收到情报，排我前面的家伙已挂，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() + "获取锁成功，赶紧干活！");    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); //确保所有线程运行结束；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() {@Overridepublic void dodo() {// TODO Auto-generated method stubLOG.info("我要修改一个文件。。。。"+threadId);}});                    } catch (Exception e){                        LOG.error("【第"+threadId+"个线程】 抛出的异常：");                        e.printStackTrace();                    }                }            }.start();        }        try {//        Thread.sleep(60000);        threadSemaphore.await();            LOG.info("所有线程运行结束!");        } catch (Exception e) {            e.printStackTrace();        }    }}

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