淺談Java(SpringBoot)基于zookeeper的分布式鎖實現(xiàn)

更新時間：2019年03月13日 10:47:19 作者：LJY_SUPER

這篇文章主要介紹了Java(SpringBoot)基于zookeeper的分布式鎖實現(xiàn)，文中通過示例代碼介紹的非常詳細，對大家的學習或者工作具有一定的參考學習價值，需要的朋友們下面隨著小編來一起學習學習吧

通過zookeeper實現(xiàn)分布式鎖

1、創(chuàng)建zookeeper的client

首先通過CuratorFrameworkFactory創(chuàng)建一個連接zookeeper的連接CuratorFramework client

public class CuratorFactoryBean implements FactoryBean<CuratorFramework>, InitializingBean, DisposableBean {
 private static final Logger LOGGER = LoggerFactory.getLogger(ContractFileInfoController.class);

 private String connectionString;
 private int sessionTimeoutMs;
 private int connectionTimeoutMs;
 private RetryPolicy retryPolicy;
 private CuratorFramework client;

 public CuratorFactoryBean(String connectionString) {
  this(connectionString, 500, 500);
 }

 public CuratorFactoryBean(String connectionString, int sessionTimeoutMs, int connectionTimeoutMs) {
  this.connectionString = connectionString;
  this.sessionTimeoutMs = sessionTimeoutMs;
  this.connectionTimeoutMs = connectionTimeoutMs;
 }

 @Override
 public void destroy() throws Exception {
  LOGGER.info("Closing curator framework...");
  this.client.close();
  LOGGER.info("Closed curator framework.");
 }

 @Override
 public CuratorFramework getObject() throws Exception {
  return this.client;
 }

 @Override
 public Class<?> getObjectType() {
   return this.client != null ? this.client.getClass() : CuratorFramework.class;
 }

 @Override
 public boolean isSingleton() {
  return true;
 }

 @Override
 public void afterPropertiesSet() throws Exception {
  if (StringUtils.isEmpty(this.connectionString)) {
   throw new IllegalStateException("connectionString can not be empty.");
  } else {
   if (this.retryPolicy == null) {
    this.retryPolicy = new ExponentialBackoffRetry(1000, 2147483647, 180000);
   }

   this.client = CuratorFrameworkFactory.newClient(this.connectionString, this.sessionTimeoutMs, this.connectionTimeoutMs, this.retryPolicy);
   this.client.start();
   this.client.blockUntilConnected(30, TimeUnit.MILLISECONDS);
  }
 }
 public void setConnectionString(String connectionString) {
  this.connectionString = connectionString;
 }

 public void setSessionTimeoutMs(int sessionTimeoutMs) {
  this.sessionTimeoutMs = sessionTimeoutMs;
 }

 public void setConnectionTimeoutMs(int connectionTimeoutMs) {
  this.connectionTimeoutMs = connectionTimeoutMs;
 }

 public void setRetryPolicy(RetryPolicy retryPolicy) {
  this.retryPolicy = retryPolicy;
 }

 public void setClient(CuratorFramework client) {
  this.client = client;
 }
}

2、封裝分布式鎖

根據(jù)CuratorFramework創(chuàng)建InterProcessMutex（分布式可重入排它鎖）對一行數(shù)據(jù)進行上鎖

 public InterProcessMutex(CuratorFramework client, String path) {
  this(client, path, new StandardLockInternalsDriver());
 }

使用 acquire方法
1、acquire() :入?yún)榭?，調(diào)用該方法后，會一直堵塞，直到搶奪到鎖資源，或者zookeeper連接中斷后，上拋異常。
2、acquire(long time, TimeUnit unit)：入?yún)魅氤瑫r時間、單位，搶奪時，如果出現(xiàn)堵塞，會在超過該時間后，返回false。

 public void acquire() throws Exception {
  if (!this.internalLock(-1L, (TimeUnit)null)) {
   throw new IOException("Lost connection while trying to acquire lock: " + this.basePath);
  }
 }

 public boolean acquire(long time, TimeUnit unit) throws Exception {
  return this.internalLock(time, unit);
 }

釋放鎖 mutex.release();

public void release() throws Exception {
  Thread currentThread = Thread.currentThread();
  InterProcessMutex.LockData lockData = (InterProcessMutex.LockData)this.threadData.get(currentThread);
  if (lockData == null) {
   throw new IllegalMonitorStateException("You do not own the lock: " + this.basePath);
  } else {
   int newLockCount = lockData.lockCount.decrementAndGet();
   if (newLockCount <= 0) {
    if (newLockCount < 0) {
     throw new IllegalMonitorStateException("Lock count has gone negative for lock: " + this.basePath);
    } else {
     try {
      this.internals.releaseLock(lockData.lockPath);
     } finally {
      this.threadData.remove(currentThread);
     }

    }
   }
  }
 }

封裝后的DLock代碼
1、調(diào)用InterProcessMutex processMutex = dLock.mutex(path);

2、手動釋放鎖processMutex.release();

3、需要手動刪除路徑dLock.del(path);

推薦使用：
都是函數(shù)式編程
在業(yè)務代碼執(zhí)行完畢后會釋放鎖和刪除path
1、這個有返回結(jié)果
public T mutex(String path, ZkLockCallback zkLockCallback, long time, TimeUnit timeUnit)
2、這個無返回結(jié)果
public void mutex(String path, ZkVoidCallBack zkLockCallback, long time, TimeUnit timeUnit)

public class DLock {
 private final Logger logger;
 private static final long TIMEOUT_D = 100L;
 private static final String ROOT_PATH_D = "/dLock";
 private String lockRootPath;
 private CuratorFramework client;

 public DLock(CuratorFramework client) {
  this("/dLock", client);
 }

 public DLock(String lockRootPath, CuratorFramework client) {
  this.logger = LoggerFactory.getLogger(DLock.class);
  this.lockRootPath = lockRootPath;
  this.client = client;
 }
 public InterProcessMutex mutex(String path) {
  if (!StringUtils.startsWith(path, "/")) {
   path = Constant.keyBuilder(new Object[]{"/", path});
  }

  return new InterProcessMutex(this.client, Constant.keyBuilder(new Object[]{this.lockRootPath, "", path}));
 }

 public <T> T mutex(String path, ZkLockCallback<T> zkLockCallback) throws ZkLockException {
  return this.mutex(path, zkLockCallback, 100L, TimeUnit.MILLISECONDS);
 }

 public <T> T mutex(String path, ZkLockCallback<T> zkLockCallback, long time, TimeUnit timeUnit) throws ZkLockException {
  String finalPath = this.getLockPath(path);
  InterProcessMutex mutex = new InterProcessMutex(this.client, finalPath);

  try {
   if (!mutex.acquire(time, timeUnit)) {
    throw new ZkLockException("acquire zk lock return false");
   }
  } catch (Exception var13) {
   throw new ZkLockException("acquire zk lock failed.", var13);
  }

  T var8;
  try {
   var8 = zkLockCallback.doInLock();
  } finally {
   this.releaseLock(finalPath, mutex);
  }

  return var8;
 }

 private void releaseLock(String finalPath, InterProcessMutex mutex) {
  try {
   mutex.release();
   this.logger.info("delete zk node path:{}", finalPath);
   this.deleteInternal(finalPath);
  } catch (Exception var4) {
   this.logger.error("dlock", "release lock failed, path:{}", finalPath, var4);
//   LogUtil.error(this.logger, "dlock", "release lock failed, path:{}", new Object[]{finalPath, var4});
  }

 }

 public void mutex(String path, ZkVoidCallBack zkLockCallback, long time, TimeUnit timeUnit) throws ZkLockException {
  String finalPath = this.getLockPath(path);
  InterProcessMutex mutex = new InterProcessMutex(this.client, finalPath);

  try {
   if (!mutex.acquire(time, timeUnit)) {
    throw new ZkLockException("acquire zk lock return false");
   }
  } catch (Exception var13) {
   throw new ZkLockException("acquire zk lock failed.", var13);
  }

  try {
   zkLockCallback.response();
  } finally {
   this.releaseLock(finalPath, mutex);
  }

 }

 public String getLockPath(String customPath) {
  if (!StringUtils.startsWith(customPath, "/")) {
   customPath = Constant.keyBuilder(new Object[]{"/", customPath});
  }

  String finalPath = Constant.keyBuilder(new Object[]{this.lockRootPath, "", customPath});
  return finalPath;
 }

 private void deleteInternal(String finalPath) {
  try {
   ((ErrorListenerPathable)this.client.delete().inBackground()).forPath(finalPath);
  } catch (Exception var3) {
   this.logger.info("delete zk node path:{} failed", finalPath);
  }

 }

 public void del(String customPath) {
  String lockPath = "";

  try {
   lockPath = this.getLockPath(customPath);
   ((ErrorListenerPathable)this.client.delete().inBackground()).forPath(lockPath);
  } catch (Exception var4) {
   this.logger.info("delete zk node path:{} failed", lockPath);
  }

 }
}

@FunctionalInterface
public interface ZkLockCallback<T> {
 T doInLock();
}

@FunctionalInterface
public interface ZkVoidCallBack {
 void response();
}

public class ZkLockException extends Exception {
 public ZkLockException() {
 }

 public ZkLockException(String message) {
  super(message);
 }

 public ZkLockException(String message, Throwable cause) {
  super(message, cause);
 }
}

配置CuratorConfig

@Configuration
public class CuratorConfig {
 @Value("${zk.connectionString}")
 private String connectionString;

 @Value("${zk.sessionTimeoutMs:500}")
 private int sessionTimeoutMs;

 @Value("${zk.connectionTimeoutMs:500}")
 private int connectionTimeoutMs;

 @Value("${zk.dLockRoot:/dLock}")
 private String dLockRoot;

 @Bean
 public CuratorFactoryBean curatorFactoryBean() {
  return new CuratorFactoryBean(connectionString, sessionTimeoutMs, connectionTimeoutMs);
 }

 @Bean
 @Autowired
 public DLock dLock(CuratorFramework client) {
  return new DLock(dLockRoot, client);
 }
}

測試代碼

@RestController
@RequestMapping("/dLock")
public class LockController {

 @Autowired
 private DLock dLock;

 @RequestMapping("/lock")
 public Map testDLock(String no){
  final String path = Constant.keyBuilder("/test/no/", no);
  Long mutex=0l;
  try {
   System.out.println("在拿鎖："+path+System.currentTimeMillis());
    mutex = dLock.mutex(path, () -> {
    try {
     System.out.println("拿到鎖了" + System.currentTimeMillis());
     Thread.sleep(10000);
     System.out.println("操作完成了" + System.currentTimeMillis());
    } finally {
     return System.currentTimeMillis();
    }
   }, 1000, TimeUnit.MILLISECONDS);
  } catch (ZkLockException e) {
   System.out.println("拿不到鎖呀"+System.currentTimeMillis());
  }
  return Collections.singletonMap("ret",mutex);
 }

 @RequestMapping("/dlock")
 public Map testDLock1(String no){
  final String path = Constant.keyBuilder("/test/no/", no);
  Long mutex=0l;
  try {
   System.out.println("在拿鎖："+path+System.currentTimeMillis());
   InterProcessMutex processMutex = dLock.mutex(path);
   processMutex.acquire();
   System.out.println("拿到鎖了" + System.currentTimeMillis());
   Thread.sleep(10000);
   processMutex.release();
   System.out.println("操作完成了" + System.currentTimeMillis());
  } catch (ZkLockException e) {
   System.out.println("拿不到鎖呀"+System.currentTimeMillis());
   e.printStackTrace();
  }catch (Exception e){
   e.printStackTrace();
  }
  return Collections.singletonMap("ret",mutex);
 }
 @RequestMapping("/del")
 public Map delDLock(String no){
  final String path = Constant.keyBuilder("/test/no/", no);
  dLock.del(path);
  return Collections.singletonMap("ret",1);
 }
}

以上所述是小編給大家介紹的Java(SpringBoot)基于zookeeper的分布式鎖實現(xiàn)詳解整合，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對腳本之家網(wǎng)站的支持！

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