ZooKeeper使用小记

下载安装

下载

进入官方下载网站，选择最近的稳定版进行下载

软件要求

安装jdk，且版本在java7以上

安装

单机部署

1. 将下载好的文件放到对应目录，linux系统一般将该文件放在/user/local下面
2. 解压文件：

tar xzvf apache-zookeeper-3.5.5-bin.tar.gz

3. 创建配置文件conf/zoo.cfg

tickTime=2000
dataDir=/var/lib/zookeeper
clientPort=2181

• tickTime单位是毫秒，用于心跳检测，最小超时时间为两倍的tickTime。
• dataDir指定一个已经存在的空目录，存储zookeeper内存数据库的快照以及日志文件。
• clientPort指定一个端口，监听客户端的连接请求。

4. 启动zookeeper

bin/zkServer.sh start

管理zookeeper存储

连接到zookeeper

bin/zkCli.sh -server 127.0.0.1:2181

list指令

ls /

创建一个新的znode，关联数据"my_data"字符串

create /zk_test my_data

查看znode关联的数据

get /zk_test

设置znode关联的数据

set /zk_test junk

删除znode

delete /zk_test

Java客户端

maven加入zookeeper依赖

  org.apache.zookeeper
  zookeeper
  3.5.5

• 客户端版本最好与服务端版本一致

代码示例

1. 创建znode

public class ZooKeeperClient {
    
    private static ZooKeeper zooKeeper;
    
    public static void main(String[] args){
        try {
            zooKeeper = new ZooKeeper("120.78.228.80:3181",5000, new Watcher() {
                
                @Override
                public void process(WatchedEvent event) {
                    try {
                        if(event.getState() == KeeperState.SyncConnected) {
                            String msg = zooKeeper.create("/zk_test", "my_data".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
                            System.out.println(msg);
                        }
                    } catch (KeeperException e) {
                        e.printStackTrace();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            });
            try {
                Thread.sleep(100000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

2. 查看znode关联的数据

public class ZooKeeperClient {
    
    private static ZooKeeper zooKeeper;
    
    public static void main(String[] args){
        try {
            zooKeeper = new ZooKeeper("120.78.228.80:3181",5000, new Watcher() {
                
                @Override
                public void process(WatchedEvent event) {
                    try {
                        if(event.getState() == KeeperState.SyncConnected) {
                            byte[] bytes = zooKeeper.getData("/zk_test", false, null);
                            System.out.println(new String(bytes));
                        }
                    } catch (KeeperException e) {
                        e.printStackTrace();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            });
            try {
                Thread.sleep(100000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

3. 设置znode关联的数据

public class ZooKeeperClient {
    
    private static ZooKeeper zooKeeper;
    
    public static void main(String[] args){
        try {
            zooKeeper = new ZooKeeper("120.78.228.80:3181",5000, new Watcher() {
                
                @Override
                public void process(WatchedEvent event) {
                    try {
                        if(event.getState() == KeeperState.SyncConnected) {
                            zooKeeper.setData("/zk_test", "junk".getBytes(), -1);
                        }
                    } catch (KeeperException e) {
                        e.printStackTrace();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            });
            try {
                Thread.sleep(100000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

4. 删除znode

public class ZooKeeperClient {
    
    private static ZooKeeper zooKeeper;
    
    public static void main(String[] args){
        try {
            zooKeeper = new ZooKeeper("120.78.228.80:3181",5000, new Watcher() {
                
                @Override
                public void process(WatchedEvent event) {
                    try {
                        if(event.getState() == KeeperState.SyncConnected) {
                            zooKeeper.delete("/zk_test", -1);
                        }
                    } catch (KeeperException e) {
                        e.printStackTrace();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            });
            try {
                Thread.sleep(100000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

配置

关闭管理台入口

编辑配置文件conf/zoo.cfg

admin.enableServer=false

参考资料

• zookeeper官方文档：https://zookeeper.apache.org/doc/current/index.html
• Zookeeper原生API使用