ZooKeeper入门(四)实现分布式锁
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                                ZooKeeper入门(四)实现分布式锁
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                                首先是引入pom依賴:
<dependency><groupId>com.101tec</groupId><artifactId>zkclient</artifactId><version>0.10</version></dependency>接下來是java代碼:
1.寫一個獲取鎖和釋放鎖的接口:
public interface Lock {//獲取到鎖的資源public void getLock();// 釋放鎖public void unLock(); }2.寫一個抽象類實現這個接口:
import org.I0Itec.zkclient.ZkClient;public abstract class ZookeeperAbstractLock implements Lock {// zk連接地址private static final String CONNECTSTRING = "127.0.0.1:2181";// 創建zk連接protected ZkClient zkClient = new ZkClient(CONNECTSTRING);@Overridepublic void getLock() {if (tryLock()) {System.out.println("獲取到鎖資源...");} else {// 等待waitLock();// 重新獲取鎖資源getLock();}}@Overridepublic void unLock() {if (zkClient != null) {zkClient.close();System.out.println("釋放鎖資源...");}}// 獲取鎖資源abstract boolean tryLock();// 等待abstract void waitLock();}?3.再接一個集成類,重寫tryLock()和waitLock()
import java.util.concurrent.CountDownLatch;import org.I0Itec.zkclient.IZkDataListener;public class ZookeeperDistrbuteLock extends ZookeeperAbstractLock {private CountDownLatch countDownLatch = null;protected static final String PATH = "/qushen123";@Overrideboolean tryLock() {try {zkClient.createEphemeral(PATH);return true;} catch (Exception e) { // e.printStackTrace();return false;}}@Overridevoid waitLock() {IZkDataListener izkDataListener = new IZkDataListener() {public void handleDataDeleted(String path) throws Exception {// 喚醒被等待的線程if (countDownLatch != null) {countDownLatch.countDown();}}public void handleDataChange(String path, Object data) throws Exception {}};// 注冊事件zkClient.subscribeDataChanges(PATH, izkDataListener);if (zkClient.exists(PATH)) {countDownLatch = new CountDownLatch(1);try {countDownLatch.await();} catch (Exception e) {e.printStackTrace();}}// 刪除監聽zkClient.unsubscribeDataChanges(PATH, izkDataListener);}}?4.到這里,所有的Zookeeper分布式工具都寫完了,現在寫一個主方法,并用多線程模擬多臺服務器,使用分布式鎖,便可以實現訂單賬號的唯一性。
import java.text.SimpleDateFormat; import java.util.Date;public class OrderService implements Runnable {private static int count=1;private Lock lock = new ZookeeperDistrbuteLock();public String getNumber() {try {lock.getLock();SimpleDateFormat simpt = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");String format=simpt.format(new Date());count++;System.out.println(format);return format;} catch (Exception e) {e.printStackTrace();return "error";}finally {lock.unLock();}};public void run() {System.out.println(getNumber());};public static void main(String[] args) {System.out.println("####生成唯一訂單號###");for (int i = 0; i < 10000; i++) {new Thread( new OrderService()).start();}} }?
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