springBoot应用zookeeper进行节点配置更改的通知事件

一：linux服务器下安装zookeeper

wget http://www.apache.org/dist/zookeeper/zookeeper-3.3.3/zookeeper-3.3.3.tar.gz
tar zxvf zookeeper-3.3.3.tar.gz

注意如果上面的wget命令执行后提示404错误，那么就复制上面地址的前半部分到浏览器打开：
http://www.apache.org/dist/zookeeper/
选择要下载的zookeeper版本，赋值taz地址拼接host如下：
http://www.apache.org/dist/zookeeper/zookeeper-3.4.12/zookeeper-3.4.12.tar.gz

二：修改初始配置文件名称

# cd zookeeper-3.4.12
# cp conf/zoo_sample.cfg conf/zoo.cfg

三：启动zookeeper

# bin/zkServer.sh start

四：检测是否成功启动，用zookeeper客户端连接下服务端

# bin/zkCli.sh

如出现一下信息说明成功

五：停止服务

# bin/zkServer.sh stop

Zookeeper使用
使用客户端命令操作zookeeper
1、使用 ls 命令来查看当前 ZooKeeper 中所包含的内容

pom.xml追加zookeeper依赖

       <dependency>
			<groupId>org.apache.zookeeper</groupId>
			<artifactId>zookeeper</artifactId>
			<version>3.4.14</version>
		</dependency>

1、在zookeeper里增加一个目录节点，并且把配置信息存储在里面

2、启动两个zookeeper客户端程序，代码如下所示

import java.util.concurrent.CountDownLatch;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.EventType;
import org.apache.zookeeper.Watcher.Event.KeeperState;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;
 
/**
 * 分布式配置中心demo
 * @author 
 *
 */
public class ZooKeeperProSync implements Watcher {
 
    private static CountDownLatch connectedSemaphore = new CountDownLatch(1);
    private static ZooKeeper zk = null;
    private static Stat stat = new Stat();
 
    public static void main(String[] args) throws Exception {
        //zookeeper配置数据存放路径
        String path = "/username";
        //连接zookeeper并且注册一个默认的监听器
        zk = new ZooKeeper("192.168.31.100:2181", 5000, //
                new ZooKeeperProSync());
        //等待zk连接成功的通知
        connectedSemaphore.await();
        //获取path目录节点的配置数据，并注册默认的监听器
        System.out.println(new String(zk.getData(path, true, stat)));
 
        Thread.sleep(Integer.MAX_VALUE);
    }
 
    public void process(WatchedEvent event) {
        if (KeeperState.SyncConnected == event.getState()) {  //zk连接成功通知事件
            if (EventType.None == event.getType() && null == event.getPath()) {
                connectedSemaphore.countDown();
            } else if (event.getType() == EventType.NodeDataChanged) {  //zk目录节点数据变化通知事件
                try {
                    System.out.println("配置已修改，新值为：" + new String(zk.getData(event.getPath(), true, stat)));
                } catch (Exception e) {
                }
            }
        }
    }
}

我们在zookeeper里修改下目录节点/username下的数据值，如下所示

运行zookeeper服务

end！