133 lines
4.1 KiB
Java
133 lines
4.1 KiB
Java
package io.github.ehlxr.zkrwlock.v1;
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import org.apache.zookeeper.*;
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import org.apache.zookeeper.data.Stat;
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import java.io.Closeable;
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import java.io.IOException;
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import java.util.List;
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public abstract class ZkLock implements Closeable {
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private static final String ROOTLOCK = "/lock";
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protected static final String READ_WRITE_LOCK_PATH = "/lock/readWriteLock";
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protected static final String SERVER = "EUREKA01:2181";
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protected static final Integer TIMEOUT= 20000;
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protected static ZooKeeper zooKeeper;
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// 如果断开链接了，就需要全部暂停等待zk锁从新链接成功
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private static final Object reconnectLock = new Object();
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protected String path ;
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Watcher watcher = event -> {
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if (event.getType() == Watcher.Event.EventType.None) {
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if (event.getState() == Watcher.Event.KeeperState.SyncConnected) {
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System.out.println("重新连接成功!");
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synchronized (reconnectLock){
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reconnectLock.notifyAll();
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}
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}
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}
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};
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static {
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try {
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zooKeeper = new ZooKeeper(SERVER, TIMEOUT,event -> {
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if (event.getState() == Watcher.Event.KeeperState.SyncConnected) {
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System.out.println("重新连接成功!");
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synchronized (reconnectLock){
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reconnectLock.notifyAll();
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}
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}
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});
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}catch (Exception e){
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System.out.println("创建zk失败");
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}
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}
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public ZkLock() throws Exception {
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init();
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}
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public void init() throws Exception{
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try {
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// 创建持久节点 /lock
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if (zooKeeper.exists(ROOTLOCK, false) == null){
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zooKeeper.create(ROOTLOCK, "".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
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}
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// 创建持久节点 /lock/unfairLock
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if (zooKeeper.exists(READ_WRITE_LOCK_PATH, false) == null){
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zooKeeper.create(READ_WRITE_LOCK_PATH, "".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
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}
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}catch (Exception e){
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System.out.println(e);
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if (e instanceof KeeperException.ConnectionLossException){
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// zookeeper 服务端断开连接，等待重新链接
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synchronized (reconnectLock){
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reconnectLock.wait();
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}
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init();
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}
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}
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}
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@Override
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public void close() throws IOException {
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try {
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zooKeeper.delete(path, -1);
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} catch (InterruptedException e) {
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e.printStackTrace();
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} catch (KeeperException e) {
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e.printStackTrace();
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}
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}
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protected void cirLock(String path, List<String> list, int index) throws Exception {
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// 监听上一个读锁
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String lastPath = list.get(index - 1);
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Stat stat = zooKeeper.exists(READ_WRITE_LOCK_PATH + "/" + lastPath, event -> {
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// KeeperState DisConnected Exipred 发生，临时节点可能也会被删除
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if (event.getType() == Watcher.Event.EventType.NodeDeleted) {
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synchronized (this) {
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this.notify();
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}
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}
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if (event.getState() == Watcher.Event.KeeperState.Disconnected ||
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event.getState() == Watcher.Event.KeeperState.Expired){
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System.out.println("掉线了，重新链接");
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try {
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zooKeeper = new ZooKeeper(SERVER, TIMEOUT,watcher);
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} catch (IOException e) {
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e.printStackTrace();
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}
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}
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});
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if (stat == null) {
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// 上一个节点消失了，再次重新获取锁
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attemptLock(path);
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} else {
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// 阻塞，等待锁释放
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synchronized (this) {
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this.wait();
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}
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attemptLock(path);
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}
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}
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protected abstract void attemptLock(String path) throws Exception;
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}
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