zookeeper入门——安装启动基础操作及java案例

清疚 2023-10-04 11:50 61阅读 0赞

## 简介 ##

最近做的项目用的是zookeeper+kafka，大致学习了下zookeeper。像Spring有IOC和AOP一样，zookeeper的核心主要是文件结构和监听机制

## 安装 ##

Zookeeper 的安装还是比较简单的，注意安装目录不要有中文和空格即可

附上[安装包][Link 1]

## 启动 ##

Windows系统双击zkServer.cmd启动

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA0Nzk5ODk_size_16_color_FFFFFF_t_70][]

启动闪退的话，右键编辑zkServer.cmd，在末尾加上pause

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA0Nzk5ODk_size_16_color_FFFFFF_t_70 1][]

保存后继续双击运行，一般会有报错产生，没有报错说明正常启动

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA0Nzk5ODk_size_16_color_FFFFFF_t_70 2][]

提示找不到配置文件，需要在config中修改配置文件

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA0Nzk5ODk_size_16_color_FFFFFF_t_70 3][]

将zoo\_sample.cfg文件复制一份重命名为zoo.cfg，右键编辑

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA0Nzk5ODk_size_16_color_FFFFFF_t_70 4][]

这样双击zkServer.cmd就可以正常启动了

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA0Nzk5ODk_size_16_color_FFFFFF_t_70 5][]

## 常用操作 ##

双击zkCli.cmd启动客户端

1.ls 查看指定路径下的节点

![20210425184508692.png][]

![20210425184508695.png][]

2.create：创建一个节点

![20210425184508673.png][]

创建内容为test的/newnode节点

3.get：显示指定路径下节点的信息

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA0Nzk5ODk_size_16_color_FFFFFF_t_70 6][]

4.set：设置节点的内容

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA0Nzk5ODk_size_16_color_FFFFFF_t_70 7][]

可以和get的节点对比看下

5.delete：删除一个节点

![20210425184508704.png][]

## java案例 ##

熟悉了zookeeper的常用操作后，我们基于zookeeper的文件结构和监听机制来用java模拟下服务节点的动态上下线。熟悉SpringCloud的小伙伴可能清楚，我们微服务架构下的EurekaService会在单独服务启动成功后，自动在注册中心显示，服务下线后会自动在注册中心下线，下面代码就是模拟了这种服务的发现与注销

<dependency>
        <groupId>org.apache.zookeeper</groupId>
        <artifactId>zookeeper</artifactId>
        <version>3.4.6</version>
    </dependency>

服务端

import org.apache.zookeeper.KeeperException;
    import org.apache.zookeeper.WatchedEvent;
    import org.apache.zookeeper.Watcher;
    import org.apache.zookeeper.ZooKeeper;
    import java.util.ArrayList;
    import java.util.List;
    
    public class ZookeeperServer {
        static ZooKeeper zooKeeper;
        public static void main(String[] args) {
            try {
                String connectString = "localhost:2181";
                int sessionTimeout = 5000;
                zooKeeper = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
                    public void process(WatchedEvent watchedEvent) {
                        String path = "/servers";
                        try {
                            List<String> childrens  = zooKeeper.getChildren(path, true);
                            List<String> hosts = new ArrayList<String>();
                            for (String child : childrens) {
                                byte[] dataByte = zooKeeper.getData(path+"/"+child, false, null);
                                hosts.add(new String(dataByte));
                            }
                            System.out.println("启动服务:"+hosts);
                        } catch (KeeperException e) {
                            e.printStackTrace();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                });
                Thread.sleep(Long.MAX_VALUE);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

客户端

import org.apache.zookeeper.CreateMode;
    import org.apache.zookeeper.KeeperException;
    import org.apache.zookeeper.WatchedEvent;
    import org.apache.zookeeper.Watcher;
    import org.apache.zookeeper.ZooDefs;
    import org.apache.zookeeper.ZooKeeper;
    
    public class ZookeeperClient {
        static ZooKeeper zooKeeper;
        public static void main(String[] args) {
            try {
                String connectString = "localhost:2181";
                int sessionTimeout = 5000;
                zooKeeper = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
                    public void process(WatchedEvent watchedEvent) {
                        // 启动userService服务
                        String serviceName = "userService";
                        // 设置服务目录
                        String path = "/servers/node";
                        try {
                            zooKeeper.create(path, serviceName.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);
                        } catch (KeeperException e) {
                            e.printStackTrace();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                });
                Thread.sleep(Long.MAX_VALUE);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

先通过zkCli.cmd创建servers节点

create /servers ""

![20210425184508719.png][]

启动ZookeeperServer监听服务，然后启动ZookeeperClient的用户服务，还可以通过zkCli.cmd创建其他节点，打印日志如下

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA0Nzk5ODk_size_16_color_FFFFFF_t_70 8][]

## 其他 ##

好了今天的zookeeper入门就到这里了，大家有什么问题和建议可以一起沟通下，不想安装环境的可以找我连向日葵练习:)

[Link 1]: https://download.csdn.net/download/u010479989/17896988
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[20210425184508692.png]: https://img-blog.csdnimg.cn/20210425184508692.png
[20210425184508695.png]: https://img-blog.csdnimg.cn/20210425184508695.png
[20210425184508673.png]: https://img-blog.csdnimg.cn/20210425184508673.png
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[20210425184508704.png]: https://img-blog.csdnimg.cn/20210425184508704.png
[20210425184508719.png]: https://img-blog.csdnimg.cn/20210425184508719.png
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