浅谈Java(SpringBoot)基于zookeeper的分布式锁实现

通过zookeeper实现分布式锁

1、创建zookeeper的client

首先通过curatorframeworkfactory创建一个连接zookeeper的连接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、封装分布式锁

根据curatorframework创建interprocessmutex（分布式可重入排它锁）对一行数据进行上锁

 public interprocessmutex(curatorframework client, string path) {
  this(client, path, new standardlockinternalsdriver());
 }

使用 acquire方法
1、acquire() :入参为空，调用该方法后，会一直堵塞，直到抢夺到锁资源，或者zookeeper连接中断后，上抛异常。
2、acquire(long time, timeunit unit)：入参传入超时时间、单位，抢夺时，如果出现堵塞，会在超过该时间后，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);
 }

释放锁 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);
     }

    }
   }
  }
 }

封装后的dlock代码
1、调用interprocessmutex processmutex = dlock.mutex(path);

2、手动释放锁processmutex.release();

3、需要手动删除路径dlock.del(path);

推荐 使用：
都是 函数式编程
在业务代码执行完毕后 会释放锁和删除path
1、这个有返回结果
public t mutex(string path, zklockcallback zklockcallback, long time, timeunit timeunit)
2、这个无返回结果
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);
 }
}

测试代码

@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("在拿锁："+path+system.currenttimemillis());
    mutex = dlock.mutex(path, () -> {
    try {
     system.out.println("拿到锁了" + 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("拿不到锁呀"+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("在拿锁："+path+system.currenttimemillis());
   interprocessmutex processmutex = dlock.mutex(path);
   processmutex.acquire();
   system.out.println("拿到锁了" + system.currenttimemillis());
   thread.sleep(10000);
   processmutex.release();
   system.out.println("操作完成了" + system.currenttimemillis());
  } catch (zklockexception e) {
   system.out.println("拿不到锁呀"+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);
 }
}

以上所述是小编给大家介绍的java(springboot)基于zookeeper的分布式锁实现详解整合，希望对大家有所帮助