zookeeper集群节点中Java程序代码写入节点数据

妖狐艹你老母 2024-04-17 05:32 57阅读 0赞

基于IDEA开发。需要添加对zookeeper的maven引用。

<dependencies>
            <dependency>
                <groupId>org.apache.zookeeper</groupId>
                <artifactId>zookeeper</artifactId>
                <version>3.5.5</version>
            </dependency>
    
            <dependency>
                <groupId>org.apache.logging.log4j</groupId>
                <artifactId>log4j-core</artifactId>
                <version>2.12.1</version>
            </dependency>
        </dependencies>

添加log4j是因为zookeeper内部引用，需要在pom.xml添加。

Java代码：

import org.apache.zookeeper.*;
    import org.apache.zookeeper.data.Stat;
    
    public class Main {
        private ZooKeeper mZooKeeper;
    
        public static void main(String[] args) {
            //初始化log4j，zookeeper否则报错。
            org.apache.log4j.BasicConfigurator.configure();
    
            try {
                Main m = new Main();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        public Main() throws Exception {
            String ip = "localhost";
            String addrs = ip + ":2181," + ip + ":2182," + ip + ":2183";
    
            //连接zookeeper服务器。
            //addrs是一批地址，如果其中某一个服务器挂掉，其他仍可用。
            mZooKeeper = new ZooKeeper(addrs, 300 * 1000, new MyWatcher());
    
            synchronized (Main.class) {
                System.out.println("等待连接建立...");
                Main.class.wait();
            }
    
            System.out.println("继续执行");
    
            operation(mZooKeeper);
            //mZooKeeper.close();
        }
    
        private class MyWatcher implements Watcher {
            @Override
            public void process(WatchedEvent event) {
                if (mZooKeeper.getState() == ZooKeeper.States.CONNECTED) {
                    System.out.println("连接建立！");
    
                    synchronized (Main.class) {
                        System.out.println("唤醒主线程的等待!");
                        Main.class.notifyAll();
                    }
                }
    
                if (event.getState() == Event.KeeperState.SyncConnected) {
                    System.out.println("状态:" + Event.KeeperState.SyncConnected);
                }
            }
        }
    
        private void operation(ZooKeeper zk) throws Exception {
            if (zk.getState().equals(ZooKeeper.States.CONNECTED)) {
                System.out.println("已经连接到zookeeper服务器");
            } else {
                System.out.println("连接zookeeper服务器失败!");
    
                return;
            }
    
            String node = "/zhang_phil_node";
            String data = "hello,world!";
    
            //检测node节点是否存在。
            Stat stat = zk.exists(node, false);
    
            if (stat == null) {
                //创建节点。
                String result = zk.create(node, data.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
                System.out.println(result);
            }
    
            //获取节点的值。
            byte[] b = zk.getData(node, false, stat);
            System.out.println(new String(b));
    
            zk.close();
        }
    }

本例实现一个简单功能，往zookeeper集群中写入一个zhang\_phil\_node节点，同时设置该节点下数据为 hello,world!

Java程序跑之前，需要把zookeeper集群启动。程序跑完后，命令行进入zookeeper，检测本例的程序代码是否添加数据成功：

![20190822161241813.png][]

表明写入zookeeper集群中的数据成功。

[20190822161241813.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/11/3275e662020f42e98dd3e505ff793945.png