通过zookeeper监听器做到监听数据改变而去修改更新实时内存数据

素颜马尾好姑娘i 2024-04-17 19:29 57阅读 0赞

1，监听器简单代码，需要测试

>     package com.coder.flink.core.a_zk;
>     
>     import org.apache.curator.framework.CuratorFramework;
>     import org.apache.curator.framework.CuratorFrameworkFactory;
>     import org.apache.curator.framework.recipes.cache.ChildData;
>     import org.apache.curator.framework.recipes.cache.NodeCache;
>     import org.apache.curator.framework.recipes.cache.NodeCacheListener;
>     import org.apache.curator.retry.ExponentialBackoffRetry;
>     import org.apache.curator.utils.EnsurePath;
>     
>     import java.util.concurrent.CountDownLatch;
>     
>     public class NodeCacheExample {
>         private static final String PATH = "/tmp2";
>     
>         private static CountDownLatch latch = new CountDownLatch(1);
>     
>         static NodeCache nodeCache;
>     
>         static CuratorFramework client;
>     
>         static {
>     
>             client = CuratorFrameworkFactory.newClient(
>                     "node1:2181", 5000, 5000, new ExponentialBackoffRetry(
>                             1000, 3));
>             client.start();
>         }
>     
>         public static void initCache() throws Exception {
>     //        client.create().forPath(PATH);
>     //        client.setData().forPath(PATH, "节点的初始值".getBytes());
>             nodeCache = new NodeCache(client, PATH);
>             EnsurePath ensurePath = client.newNamespaceAwareEnsurePath(PATH);
>             ensurePath.ensure(client.getZookeeperClient());
>             //设置成true,那么nodeCache在第一次启动的时候就会到zookeeper上去获取节点的数据内容，并保存在cache中
>             nodeCache.start(true);
>             startCache(nodeCache);
>         }
>     
>         private static void startCache(final NodeCache cache) throws Exception {
>     
>             ChildData data = cache.getCurrentData();
>     
>             System.out.println("第一次启动获取到的内容:"  + new String(data.getData()));
>     
>             cache.getListenable().addListener(new NodeCacheListener() {
>                 @Override
>                 public void nodeChanged() throws Exception {
>                     System.out.println("监听器获取到的数据： "
>                             + new String(cache.getCurrentData().getData()));
>                     latch.countDown();
>                 }
>             });
>            /* Thread.sleep(2000);
>             if(client.checkExists().forPath(PATH) != null){
>                 System.out.println("node is exist,准备给节点设置新的内容");
>                 client.setData().forPath(PATH, "节点新内容".getBytes());
>                 client.setData().forPath(PATH, "节点新内容2".getBytes());
>                 client.setData().forPath(PATH, "节点新内容3".getBytes());
>             }*/
>             Thread.sleep(Long.MAX_VALUE);
>         }
>     
>         public static void main(String[] args) throws Exception {
>             initCache();
>             latch.await();
>         }
>     }

>     package com.coder.flink.core.a_zk;
>     
>     import org.apache.curator.framework.CuratorFramework;
>     import org.apache.curator.framework.CuratorFrameworkFactory;
>     import org.apache.curator.framework.recipes.cache.ChildData;
>     import org.apache.curator.framework.recipes.cache.NodeCache;
>     import org.apache.curator.framework.recipes.cache.NodeCacheListener;
>     import org.apache.curator.retry.ExponentialBackoffRetry;
>     import org.apache.curator.utils.EnsurePath;
>     
>     import java.util.Date;
>     import java.util.Random;
>     import java.util.concurrent.CountDownLatch;
>     
>     public class NodeCacheExample_send {
>         private static final String PATH = "/tmp2";
>     
>         private static CountDownLatch latch = new CountDownLatch(1);
>     
>         static NodeCache nodeCache;
>     
>         static CuratorFramework client;
>     
>         static {
>     
>             client = CuratorFrameworkFactory.newClient(
>                     "node1:2181", 5000, 5000, new ExponentialBackoffRetry(
>                             1000, 3));
>             client.start();
>         }
>     
>         public static void initCache() throws Exception {
>     
>     
>     //        client.create().forPath(PATH);
>     //        client.setData().forPath(PATH, "节点的初始值".getBytes());
>     
>             nodeCache = new NodeCache(client, PATH);
>     
>     
>             EnsurePath ensurePath = client.newNamespaceAwareEnsurePath(PATH);
>             ensurePath.ensure(client.getZookeeperClient());
>             //设置成true,那么nodeCache在第一次启动的时候就会到zookeeper上去获取节点的数据内容，并保存在cache中
>             nodeCache.start(true);
>     
>     
>             setData(nodeCache);
>         }
>         //给节点赋值
>         private static void setData(final NodeCache cache) throws Exception {
>     
>             ChildData data = cache.getCurrentData();
>     
>             System.out.println("第一次启动获取到的内容:"  + new String(data.getData()));
>             Thread.sleep(2000);
>             if(client.checkExists().forPath(PATH) != null){
>                 for (int i = 0; i < 10 ; i++) {
>                     Random  random = new Random();
>     
>                     String json = "{'a':'1','type':'"+random.nextInt(3)+"'}";
>                     System.out.println("========发送的内容======【"+json+"】");
>                     client.setData().forPath(PATH, ("节点新内容:"+json).getBytes());
>                 }
>     
>     
>     
>             }
>     
>         }
>     
>         public static void main(String[] args) throws Exception {
>             initCache();
>             latch.await();
>         }
>     }

修改zookeeper的节点数据

>     package com.coder.flink.core.a_zk;
>     
>     
>     import org.apache.curator.framework.CuratorFramework;
>     import org.apache.curator.framework.CuratorFrameworkFactory;
>     import org.apache.curator.framework.recipes.cache.ChildData;
>     import org.apache.curator.framework.recipes.cache.NodeCache;
>     import org.apache.curator.framework.recipes.cache.NodeCacheListener;
>     import org.apache.curator.retry.ExponentialBackoffRetry;
>     import org.apache.curator.utils.EnsurePath;
>     import org.apache.zookeeper.*;
>     import org.apache.zookeeper.data.Stat;
>     import org.junit.Before;
>     import org.junit.Test;
>     
>     import java.io.IOException;
>     import java.util.List;
>     import java.util.Random;
>     
>     public class zkSendDataExample {
>         private static final String connectString = "node1:2181";
>         private static final int sessionTimeout = 6000;
>         static ZooKeeper zkClient = null;
>     
>     
>         /*
>          *connectString -- host:port[，host:port][basePath] 指定的服务器列表，多个host:port之间用英文逗号分隔。
>          *sessionTimeOut -- 会话超时时间。以毫秒为单位。客户端和服务器端之间的连接通过心跳包进行维系，如果心跳包超过这个指定时间则认为会话超时失效。
>          *watcher -- 监视器。如果为null表示不需要观察者。
>          */
>     
>         public static void init() throws IOException, KeeperException, InterruptedException {
>             zkClient = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
>     
>                 @Override
>                 public void process(WatchedEvent event) {
>                     //事件处理逻辑
>                     System.out.println("正在监听");
>                 }
>             });
>             byte[] data = zkClient.getData("/tmp2", new Watcher() {
>                 //监听的具体内容
>                 @Override
>                 public void process(WatchedEvent event) {
>                     System.out.println("监听路径为：" + event.getPath());
>                     System.out.println("监听的类型为：" + event.getType());
>                     System.out.println("数据被2货修改了！！！");
>                 }
>             }, null);
>     
>             System.out.println(new String(data));
>         }
>     
>     
>         public void testCreateNode() throws KeeperException, InterruptedException {
>             //进行增删改查
>     
>             /*
>              * 第一个参数：节点的路径
>              * 第二个参数：节点存放的数据
>              * 第三个参数：节点的权限
>              * 第四个参数：节点的类型（是暂时的还是持久的）
>              */
>             String newNodeString = zkClient.create("/eclipse", "111".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);
>             System.out.println("----------\n");
>         }
>     
>         //判断该节点是否存在
>     
>         public void existNode() throws KeeperException, InterruptedException {
>             /*
>              * 参数1：节点路径
>              * 参数2：是否需要监视器，若不需要填写“false”
>              */
>             Stat exists = zkClient.exists("/a0000000004", false);
>             System.out.println(exists == null ? "not exists" : "exists");
>             System.out.println("----------\n");
>         }
>     
>         //获取子节点
>     
>         public void getChildren() throws KeeperException, InterruptedException {
>             /*
>              * 参数1：节点路径
>              * 参数2：是否需要监视器，若不需要填写“false”
>              */
>             List<String> children = zkClient.getChildren("/a0000000004", true);
>             for (String child : children) {
>                 System.out.println(child);
>             }
>             System.out.println("----------\n");
>         }
>     
>         //获取节点数据
>     
>         public void nodeData() throws KeeperException, InterruptedException {
>             /*
>              * 参数1：节点路径
>              * 参数2：是否需要监视器，若不需要填写“false”
>              * 参数3：指定数据节点的状态信息：一般填写“null”或者“new stat”
>              */
>             byte[] data = zkClient.getData("/a0000000004", false, null);
>             System.out.println(new String(data));//因为存放的是byte()类型数据
>             System.out.println("----------\n");
>         }
>     
>         //删除节点
>     
>         public void deleteNode() throws InterruptedException, KeeperException {
>             /*
>              * 参数2：version，可以传入-1，表明要基于最新版本进行更新操作
>              */
>             zkClient.delete("/eclipse", -1);
>             System.out.println("----------\n");
>         }
>     
>         //修改节点数据
>     
>         public static void setNodeData(String log) throws KeeperException, InterruptedException {
>     
>             byte[] data = zkClient.getData("/tmp2", false, null);
>             System.out.println(new String(data));
>     
>             zkClient.setData("/tmp2", log.getBytes(), -1);
>             byte[] data1 = zkClient.getData("/tmp2", false, null);
>             System.out.println(new String(data1));
>         }
>     
>         public static void main(String[] args) {
>             Random random = new Random();
>             String json = "{'aaa':'1','type':'"+random.nextInt(3)+"'}";
>             System.out.println("========发送的内容======【"+json+"】");
>             try {
>                 init();
>                 setNodeData(json);
>             } catch (KeeperException e) {
>                 e.printStackTrace();
>             } catch (InterruptedException e) {
>                 e.printStackTrace();
>     
>             } catch (IOException e) {
>                 e.printStackTrace();
>             }
>         }
>     
>     }

最简单的案例：

2，修改实时内存数据也很简单 等完善了再写