ZooKeeper分布式锁和ZooKeeper集群的搭建

一、ZooKeeper分布式锁

使用Eclipse的Maven来搭建工程，注意使用这种方式需要连接互联网，连接互联网自动下载ZK的所依赖的jar包

所需要的pom.xml文件如下

<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	</properties>

	<dependencies>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>3.8.1</version>
			<scope>test</scope>
		</dependency>

		<dependency>
			<groupId>org.apache.curator</groupId>
			<artifactId>curator-framework</artifactId>
			<version>4.0.0</version>
		</dependency>

		<dependency>
			<groupId>org.apache.curator</groupId>
			<artifactId>curator-recipes</artifactId>
			<version>4.0.0</version>
		</dependency>

		<dependency>
			<groupId>org.apache.curator</groupId>
			<artifactId>curator-client</artifactId>
			<version>4.0.0</version>
		</dependency>
		<dependency>
			<groupId>org.apache.zookeeper</groupId>
			<artifactId>zookeeper</artifactId>
			<version>3.4.6</version>
		</dependency>

		<dependency>
			<groupId>com.google.guava</groupId>
			<artifactId>guava</artifactId>
			<version>16.0.1</version>
		</dependency>

	</dependencies>

将上面的pom.xml粘贴到Eclipse中pom.xml文件中

具体的java代码如下

package com.org.lz;

import org.apache.curator.CuratorConnectionLossException;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.recipes.locks.InterProcessMutex;
import org.apache.curator.retry.ExponentialBackoffRetry;


public class DistributedLock {
	
	//定义共享资源
		private static int count = 20;
		private static void printCountNumber() {
			System.out.println("#########业务方法开始###########");
			System.out.println("当前值：" + count);
			count --;
			
			//休息2秒
			try {
				Thread.sleep(2000);
			}catch (InterruptedException ex) {
				ex.printStackTrace();
			}
			System.out.println("########业务方法结束########");
		}
		
		
	public static void main(String[] args) {
		//定义客户端重试的策略
				ExponentialBackoffRetry policy = new ExponentialBackoffRetry(1000,//每次等待的时间
																20);//最大重试的次数
						
		//定义ZK的一个客户端
		CuratorFramework client = CuratorFrameworkFactory.builder()
								  .connectString("192.168.100.11:2181")
								  .retryPolicy(policy)
								  .build();
		//在ZK生成锁     ----->  就是ZK的目录
		client.start();
		final InterProcessMutex lock = new InterProcessMutex(client,"/Threadlock");
		
		//启动20个线程去访问共享资源
		for (int i = 0 ;i<20;i++) {
			new Thread(new Runnable() {
				
				public void run() {
					try {
						//请求得到锁
						lock.acquire();
						
						//访问共享资源
						printCountNumber();
					
					}catch (Exception ex) {
						ex.printStackTrace();
					}finally {
						//释放锁
						try {
							lock.release();
						}catch (Exception ex) {
							ex.printStackTrace();
						}
					}
				}
			}).start();

		}
	}
}

运行所得到的结果如图