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java-doc-zookeeper

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编程

Zookeeper

接口难以使用，在连接zk超时，不支持自动重连；Watch注册一次会失效，需要反复注册；不支持递归创建节点，需要手动序列化

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<dependency>
    <groupId>org.apache.zookeeper</groupId>
    <artifactId>zookeeper</artifactId>
    <version>3.4.13</version>
</dependency>
  • 接口
方法 描述
connect 连接到ZooKeeper集合
create 创建znode
exists 检查znode是否存在及其信息
getData 从特定的znode获取数据
setData 在特定的znode中设置数据
getChildren 获取特定znode中的所有子节点
delete 删除特定的znode及其所有子项
close 关闭连接

Zkclient

基于原生API改造，比原生API用起来更称手

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<dependency>
    <groupId>com.101tec</groupId>
    <artifactId>zkclient</artifactId>
    <version>0.10</version>
</dependency>
  • MyZkSerializer
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package learn.zk;

import java.io.UnsupportedEncodingException;

import org.I0Itec.zkclient.exception.ZkMarshallingError;
import org.I0Itec.zkclient.serialize.ZkSerializer;

public class MyZkSerializer implements ZkSerializer {

    public byte[] serialize(Object data) throws ZkMarshallingError {
        String d = (String) data;
        try {
            return d.getBytes("UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return null;
    }

    public Object deserialize(byte[] bytes) throws ZkMarshallingError {
        try {
            return new String(bytes, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return null;
    }

}
  • ZkClientDemo
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package learn.zk;

import java.util.List;

import org.I0Itec.zkclient.IZkChildListener;
import org.I0Itec.zkclient.IZkDataListener;
import org.I0Itec.zkclient.IZkStateListener;
import org.I0Itec.zkclient.ZkClient;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.Watcher.Event.KeeperState;

public class ZkClientDemo {
    public static void main(String[] args) {
        // 创建一个zk客户端
        ZkClient client = new ZkClient("localhost:2181");
        client.setZkSerializer(new MyZkSerializer());
        client.create("/zk/app6", "123", CreateMode.PERSISTENT);

        client.subscribeChildChanges("/zk/app6", new IZkChildListener() {
            public void handleChildChange(String parentPath, List<String> currentChilds) throws Exception {
                System.out.println(parentPath+"子节点发生变化："+currentChilds);
            }
        });

        client.subscribeDataChanges("/zk/app6", new IZkDataListener() {
            public void handleDataDeleted(String dataPath) throws Exception {
                System.out.println(dataPath + "节点被删除");
            }

            public void handleDataChange(String dataPath, Object data) throws Exception {
                System.out.println(dataPath + "发生变化："+data);
            }
        });

        try {
            Thread.currentThread().join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

Curator

Curator Apache 的开源项目
解决Watch注册一次就会失效的问题
提供的 API 更加简单易用
提供更多解决方案并且实现简单，例如：分布式锁
提供常用的ZooKeeper工具类
编程风格更舒服

工具

ZooInspector

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# 下载地址
https://issues.apache.org/jira/secure/attachment/12436620/ZooInspector.zip 


# 解压缩后进入build目录运行命令
java -jar zookeeper-dev-ZooInspector.jar