Zookeeper原生java客户端

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  • maven依赖
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    <dependency>
      <groupId>org.apache.zookeeper</groupId>
      <artifactId>zookeeper</artifactId>
      <version>3.4.13</version>
    </dependency>

  • 创建Zookeeper对象

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    ZooKeeper zooKeeper = new ZooKeeper("localhost:2187", 5000, watch);
    //集群
    ZooKeeper zooKeeper = new ZooKeeper("localhost:2187,localhost:2188,localhost:2189", 5000,
             watch);
    //指定跟路径，操作/test时，其真实路径为/root/test
    ZooKeeper zooKeeper = new ZooKeeper("localhost:2187,localhost:2188,localhost:2189/root", 5000,
                totalWatch);

  • Watcher
    实现Watcher接口

  • 检查节点是否存在

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    //使用默认watch，即构建Zookeeper中的watch
    Stat exists = zooKeeper.exists(TOTAL_PATH, true);
    //使用新的watch
    Stat exists = zooKeeper.exists(TOTAL_PATH, new XxxWatch());

  • 创建节点

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    String createdPath = zooKeeper.create(PATH, "TEST".getBytes(Charsets.UTF_8), Ids.CREATOR_ALL_ACL,
                        CreateMode.EPHEMERAL);

  • 获取节点数据

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    Stat stat = new Stat();
    byte[] dataBytes = zooKeeper.getData(PATH, true, stat);
    //byte[] dataBytes = zooKeeper.getData(PATH, new XxxWatch(), stat);
    String data = new String(dataBytes, Charsets.UTF_8);

  • 删除节点

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    zooKeeper.delete(PATH, stat.getVersion());

  • 修改节点数据

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    zooKeeper.setData(PATH, "UPDATE".getBytes(Charsets.UTF_8), stat.getVersion());

  • 获取子节点

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    List<String> children = zooKeeper.getChildren("/", false);

  • 完整实例

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    package com.fei.curator;

    import com.google.common.base.Charsets;
    import java.util.ArrayList;
    import java.util.List;
    import org.apache.zookeeper.CreateMode;
    import org.apache.zookeeper.WatchedEvent;
    import org.apache.zookeeper.Watcher;
    import org.apache.zookeeper.ZooDefs.Ids;
    import org.apache.zookeeper.ZooDefs.Perms;
    import org.apache.zookeeper.ZooKeeper;
    import org.apache.zookeeper.data.ACL;
    import org.apache.zookeeper.data.Id;
    import org.apache.zookeeper.data.Stat;
    import org.apache.zookeeper.server.auth.DigestAuthenticationProvider;

    /**
     * ZookeeperTest
     *
     * @author fei
     */
    public class ZookeeperTest implements Watcher {

        private static final String PATH = "/test";
        private static final String PATH2 = "/test2";

        public static void main(String[] args) throws Exception {
            ZookeeperTest watch = new ZookeeperTest();
            //构建Zookeeper，以/root为根路径
            ZooKeeper zooKeeper = new ZooKeeper("localhost:2187,localhost:2188,localhost:2189/root",
                5000, watch);
            //ACL验证信息
            zooKeeper.addAuthInfo("digest", "root:123".getBytes(Charsets.UTF_8));
            //检查是否存在
            Stat exists = zooKeeper.exists(PATH, true);
            System.out.println(PATH + " 是否存在：" + (exists != null));
            if (exists == null) {
                String createdPath = zooKeeper.create(PATH, "TEST".getBytes(Charsets.UTF_8),
                    Ids.CREATOR_ALL_ACL, CreateMode.PERSISTENT);
                System.out.println("创建节点：" + createdPath);
            }
            //获取节点数据
            Stat stat = new Stat();
            byte[] dataBytes = zooKeeper.getData(PATH, true, stat);
            String data = new String(dataBytes, Charsets.UTF_8);
            System.out.println("节点数据为：" + data);
            System.out.println("节点版本号：" + stat.getVersion() + " ,状态为：" + stat);
            //更新节点数据
            zooKeeper.setData(PATH, "UPDATE".getBytes(Charsets.UTF_8), stat.getVersion());
            dataBytes = zooKeeper.getData(PATH, true, stat);
            data = new String(dataBytes, Charsets.UTF_8);
            System.out.println("更新后节点数据为：" + data);
            System.out.println("更新后节点版本号：" + stat.getVersion() + " ,状态为：" + stat);

            // 自定义权限
            List<ACL> acls = new ArrayList<>(1);
            Id digest = new Id("digest", DigestAuthenticationProvider.generateDigest("root:123"));
            acls.add(new ACL(Perms.READ | Perms.WRITE, digest));
            //创建/test2为顺序节点，对root可读可写.
            String node2 = zooKeeper.create(PATH2, "TEST2".getBytes(Charsets.UTF_8), acls,
                CreateMode.PERSISTENT_SEQUENTIAL);
            //获取子节点
            List<String> children = zooKeeper.getChildren("/", false);
            System.out.println("children: " + children);
            //删除节点
            zooKeeper.delete(PATH, stat.getVersion());
            zooKeeper.getData(node2, false, stat);
            zooKeeper.delete(node2, stat.getVersion());

            //验证是否删除成功
            exists = zooKeeper.exists(PATH, false);
            System.out.println(PATH + " 是否删除成功：" + (exists == null));
            exists = zooKeeper.exists(node2, false);
            System.out.println(node2 + " 是否删除成功：" + (exists == null));
        }

        @Override
        public void process(WatchedEvent event) {
            System.out.println(event.toString());
        }
    }