Android移动设备远程接入ZooKeeper分布式集群

绝地灬酷狼 2024-04-18 19:38 46阅读 0赞

## Android移动设备连接接入到zookeeper分布式集群 ##

在Android Studio中添加引用依赖：

compile group:'org.apache.zookeeper', name:'zookeeper', version:'3.5.5'

Android端代码：

package zhangphil.zookeeper;
    
    import androidx.appcompat.app.AppCompatActivity;
    
    import android.os.Bundle;
    
    import org.apache.zookeeper.CreateMode;
    import org.apache.zookeeper.WatchedEvent;
    import org.apache.zookeeper.Watcher;
    import org.apache.zookeeper.ZooDefs;
    import org.apache.zookeeper.ZooKeeper;
    import org.apache.zookeeper.client.ZooKeeperSaslClient;
    
    import java.util.concurrent.CompletableFuture;
    import java.util.concurrent.TimeUnit;
    
    public class MainActivity extends AppCompatActivity {
    
        private ZooKeeper zooKeeper;
        private String DEVICE_PATH = "/devices";
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
    
            //非常重要，如果没有，则Android手机客户端连接不到部署在PC上的ZooKeeper集群。
            System.setProperty(ZooKeeperSaslClient.ENABLE_CLIENT_SASL_KEY,"false");
    
            CompletableFuture.runAsync(new Runnable() {
                @Override
                public void run() {
                    try {
                        zk();
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            });
        }
    
        private void zk() throws Exception {
            zooKeeper = new ZooKeeper(getAddress(), 10 * 1000, new Watcher() {
                @Override
                public void process(WatchedEvent event) {
                    System.out.println(event.toString());
                }
            });
    
            System.out.println("开始连接...");
            while (!zooKeeper.getState().isConnected()) {
                TimeUnit.SECONDS.sleep(3);
                System.out.println("尝试连接...");
            }
            System.out.println("连接建立");
    
            login();
    
            synchronized (this) {
                wait();
            }
        }
    
        private void login() throws Exception {
            //创建节点。
            String path = zooKeeper.create(DEVICE_PATH + "/client", "ip:127.0.0.1".getBytes("UTF-8"), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);
            byte[] data = zooKeeper.getData(path, null, null);
            System.out.println(path + " => " + new String(data));
            System.out.println("注册设备成功");
        }
    
        private String getAddress() {
            String ip = "192.168.137.1";
            return ip + ":2181," + ip + ":2182," + ip + ":2183";
        }
    }

需要保证Android手机与PC上部署的ZooKeeper集群连通，比如，可以让Android手机与PC同处于一个局域网（共同连接到一个WIFI）。

特别注意，在Android手机上跑的ZooKeeper程序，必须显示的关闭SASL认证，否则Android手机上的Zookeeper客户端连接不到处于PC网络的ZooKeeper集群。关闭SASL其实就一行代码：

System.setProperty(ZooKeeperSaslClient.ENABLE_CLIENT_SASL_KEY,"false");

接下来运行系统。首先要启动位于PC网络的ZooKeeper集群。

在Android手机上跑起上面的程序代码输出：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly96aGFuZ3BoaWwuYmxvZy5jc2RuLm5ldA_size_16_color_FFFFFF_t_70][]

然后在PC上，通过命令行ls查询：

![20191015183007871.png][]

说明Android手机接入ZooKeeper成功。

这很有趣，一旦这条路走通，就意味着可以使用ZooKeeper做非常棒的Android设备在集群中的分布式系统应用，如，实时检测大规模集群中，某一Android设备是否在线，即心跳。

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly96aGFuZ3BoaWwuYmxvZy5jc2RuLm5ldA_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/18/b1c94a60d5ee4fca91f6fe5a58e03e40.png
[20191015183007871.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/18/4d42c901896847abbe2ddf25afc10589.png