<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.7.1</version>
</dependency>
package com.test;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.zookeeper.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.stream.Collectors;
public class ZookeeperLock implements Lock {
private static ThreadLocal<String> lockNodePathThreadLocal = new ThreadLocal<>();
private final ZooKeeper zooKeeper;
private final String basePath;
private final String lockName;
private final String pathSeparator = "/";
private Logger logger = LoggerFactory.getLogger(getClass());
public ZookeeperLock(ZooKeeper zooKeeper, String basePath, String lockName) {
this.zooKeeper = zooKeeper;
this.basePath = basePath;
this.lockName = lockName;
checkLockName(lockName);
checkBasePath(basePath);
createBasePathIfNecessary(zooKeeper, basePath);
}
private void checkLockName(String lockName) {
if(lockName.contains(pathSeparator))
throw new RuntimeException("invalid lock name, lock name should not contains " + pathSeparator);
}
private void checkBasePath(String basePath) {
if(!basePath.startsWith(pathSeparator))
throw new RuntimeException("base path must starts with " + pathSeparator);
if(!basePath.equals(pathSeparator) && basePath.endsWith("/"))
throw new RuntimeException("base path should not ends with " + pathSeparator);
}
private void createBasePathIfNecessary(ZooKeeper zooKeeper, String basePath) {
try {
String[] nodeNamesInBasePath = Arrays.stream(basePath.split(pathSeparator)).filter(s -> StringUtils.isNotBlank(s)).collect(Collectors.toList()).toArray(new String[0]);
boolean needCreate = false;
for (int i = 0; i < nodeNamesInBasePath.length; i++) {
String[] nodeNames = ArrayUtils.subarray(nodeNamesInBasePath, 0, i + 1);
String path = pathSeparator + StringUtils.join(nodeNames, pathSeparator);
if (needCreate || zooKeeper.exists(path, false) == null) {
needCreate = true;
zooKeeper.create(path, null, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
}
}
} catch (Exception e) {
throw new RuntimeException("create zookeeper base dir for lock failed!", e);
}
}
@Override
public void lock() {
while (true) {
try {
lockInterruptibly();
return;
} catch (InterruptedException e) {
logger.debug(e.getMessage(), e);
} catch (RuntimeException e) {
throw e;
}
}
}
@Override
public void lockInterruptibly() throws InterruptedException {
lockInterruptiblyInternal(0, null);
}
@Override
public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {
lockInterruptiblyInternal(time, unit);
return true;
}
@Override
public boolean tryLock() {
try {
String lockNodePath = createLockNode();
if (getLockNodePaths().indexOf(lockNodePath) == 0)
return true;
removeLockNode();
return false;
} catch (InterruptedException e) {
logger.debug(e.getMessage(), e);
return false;
} catch (KeeperException e) {
throw new RuntimeException(e);
}
}
@Override
public void unlock() {
try {
removeLockNode();
} catch (KeeperException e) {
throw new RuntimeException(e);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
}
@Override
public Condition newCondition() {
throw new UnsupportedOperationException();
}
private void lockInterruptiblyInternal(long time, TimeUnit unit) throws InterruptedException {
try {
String lockNodePath = createLockNode();
Object lock = new Object();
synchronized (lock){
while (true) {
List<String> lockNodePaths = getLockNodePaths();
int lockIndex = lockNodePaths.indexOf(lockNodePath);
if (lockIndex == 0)
return;
zooKeeper.exists(findPreviousLockNodePath(lockNodePaths, lockIndex), event -> {
