spring boot zookeeper spring boot zookeeper server

简介

         Zookeeper是一个Apache开源的分布式的应用，为系统架构提供协调服务。从设计模式角度来审视：该组件是一个基于观察者模式设计的框架，负责存储和管理数据，接受观察者的注册，一旦数据的状态发生变化，Zookeeper就将负责通知已经在Zookeeper上注册的观察者做出相应的反应，从而实现集群中类似Master/Slave管理模式。ZooKeeper的目标就是封装好复杂易出错的关键服务，将简单易用的接口和性能高效、功能稳定的系统提供给用户。

技术架构：

Spring Boot 2.6.3 、Zookeeper3.4.6 、 JDK1.8

导入依赖

<dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-framework</artifactId>
            <version>2.12.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>2.12.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-client</artifactId>
            <version>2.12.0</version>
        </dependency>
       <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.4</version>
        </dependency>

application.yml配置

zoo:
  keeper:
    #开启标志
    enabled: true
    #服务器地址
    server: 192.168.116.100:2181
    #命名空间，被称为ZNode
    namespace: lx
    #权限控制，加密
    digest: smile:111111
    #会话超时时间
    sessionTimeoutMs: 3000
    #连接超时时间
    connectionTimeoutMs: 60000
    #最大重试次数
    maxRetries: 10
    #初始休眠时间
    baseSleepTimeMs: 1000

Zookeeper配置

package com.example.zk.config;

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

/**
 * @author lanx
 * @date 2022/3/6
 */
@Data
@Component
@ConfigurationProperties(prefix = "zoo.keeper")
public class ZookeeperProperties {
    private String enabled;
    private String server;
    private String namespace;
    private String digest;
    private int sessionTimeoutMs;
    private int connectionTimeoutMs;
    private int maxRetries;
    private int baseSleepTimeMs;

}

Zookeeper 初始化

package com.example.zk.config;

import lombok.extern.slf4j.Slf4j;
import org.apache.curator.RetryPolicy;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;

import javax.annotation.PostConstruct;

/**
 * 配置
 * @author lanx
 * @date 2022/3/6
 */
@Slf4j
@Configuration
public class ZookeeperConfig {
    @Autowired
    private ZookeeperProperties zookeeperProperties ;

    private static CuratorFramework client = null ;
    /**
     * 初始化
     */
    @PostConstruct
    public void init (){
        //重试策略，初试时间1秒，重试10次
        RetryPolicy policy = new ExponentialBackoffRetry(
                zookeeperProperties.getBaseSleepTimeMs(),
                zookeeperProperties.getMaxRetries());
        //通过工厂创建Curator
        client = CuratorFrameworkFactory.builder()
                .connectString(zookeeperProperties.getServer())
                .authorization("digest",zookeeperProperties.getDigest().getBytes())
                .connectionTimeoutMs(zookeeperProperties.getConnectionTimeoutMs())
                .sessionTimeoutMs(zookeeperProperties.getSessionTimeoutMs())
                .retryPolicy(policy).build();
        //开启连接
        client.start();
        log.info("zookeeper 初始化完成...");
    }
    public static CuratorFramework getClient (){
        return client ;
    }
    public static void closeClient (){
        if (client != null){
            client.close();
        }
    }
}

Zookeeper节点数据监听

package com.example.zk.config;

import lombok.extern.slf4j.Slf4j;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.cache.*;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.stereotype.Component;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * 节点数据监听
 * @author lanx
 * @date 2022/3/6
 */
@Component
@Slf4j
public class ZookListening implements ApplicationRunner {

    @Override
    public void run(ApplicationArguments args) throws Exception {
        /**
         * 在注册监听器的时候，如果传入此参数，当事件触发时，逻辑由线程池处理
         */
        ExecutorService pool = Executors.newFixedThreadPool(2);
        /**
         * 监听数据节点的变化情况
         */
        final NodeCache nodeCache = new NodeCache(ZookeeperConfig.getClient(), "/lanxi", false);
        nodeCache.start(true);
        nodeCache.getListenable().addListener(
                /**
                 * 此方法只监听创建节点和更新节点，在删除节点是不触发此操作
                 */
                new NodeCacheListener() {
                    @Override
                    public void nodeChanged() throws Exception {
                        log.info("Node data is changed, new data: {}" ,
                                new String(nodeCache.getCurrentData().getData()));
                    }
                },
                pool
        );


        /**
         * 监听子节点的变化情况
         *
         * 建立一个PathChildrenCache的缓存，第三个参数为是否接收节点数据内容，如果为 false 则不接受
         */
        final PathChildrenCache childrenCache = new PathChildrenCache(ZookeeperConfig.getClient(), "/llx", true);
        //在初始时就进行缓存监听
        childrenCache.start(PathChildrenCache.StartMode.POST_INITIALIZED_EVENT);
        childrenCache.getListenable().addListener(
                new PathChildrenCacheListener() {
                    /**
                     * 监听节点的变更。 新建、修改、删除
                     * @param client
                     * @param event
                     * @throws Exception
                     */
                    @Override
                    public void childEvent(CuratorFramework client, PathChildrenCacheEvent event)
                            throws Exception {
                        switch (event.getType()) {
                            case CHILD_ADDED:
                                System.out.println("CHILD_ADDED: " + event.getData().getPath());
                                break;
                            case CHILD_REMOVED:
                                System.out.println("CHILD_REMOVED: " + event.getData().getPath());
                                break;
                            case CHILD_UPDATED:
                                System.out.println("CHILD_UPDATED: " + event.getData().getPath());
                                break;
                            default:
                                break;
                        }
                    }
                },
                pool
        );

    }
}

curator框架，使用 DistributedAtomicInteger 作为分布式计数器

//curator框架，使用 DistributedAtomicInteger 作为分布式计数器
        DistributedAtomicInteger atomicInteger =
                new DistributedAtomicInteger(ZookeeperConfig.getClient(), "/llx", new RetryNTimes(3, 1000));
        //复位
        atomicInteger.forceSet(0);
        AtomicValue<Integer> value = atomicInteger.add(1);
        log.info("Boolean:{}", value.succeeded());
        log.info("最新值:{}", value.postValue());
        log.info("原始值:{}", value.preValue());

curator 框架，使用 InterProcessMutex 分布式锁

for (int i = 0; i < 10; i++) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    //分布式锁
                    final InterProcessMutex lock = new InterProcessMutex(ZookeeperConfig.getClient(), "/llx");
                    try {
                        //获取锁
                        lock.acquire();
                        log.info("线程:{},执行业务逻辑", Thread.currentThread().getName());
                        Thread.sleep(1000*10);
                    } catch (Exception e) {
                        e.printStackTrace();
                    } finally {
                        try {
                            //释放锁
                            lock.release();
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                }
            }).start();
        }

Zookeeper操作Service类

package com.example.zk.service;

import org.apache.curator.framework.recipes.locks.InterProcessReadWriteLock;
import org.apache.zookeeper.CreateMode;

import java.util.List;

public interface ZookeeperService {
    /**
     * 判断节点是否存在
     */
    boolean isExistNode (final String path) ;
    /**
     * 创建节点
     */
    void createNode (CreateMode mode, String path ) ;
    /**
     * 设置节点数据
     */
    void setNodeData (String path, String nodeData) ;
    /**
     * 创建节点
     */
    void createNodeAndData (CreateMode mode, String path , String nodeData) ;
    /**
     * 获取节点数据
     */
    String getNodeData (String path) ;
    /**
     * 获取节点下数据
     */
    List<String> getNodeChild (String path) ;
    /**
     * 是否递归删除节点
     */
    void deleteNode (String path,Boolean recursive) ;
    /**
     * 获取读写锁
     */
    InterProcessReadWriteLock getReadWriteLock (String path) ;
}

package com.example.zk.service.impl;

import com.example.zk.config.ZookeeperConfig;
import com.example.zk.service.ZookeeperService;
import lombok.extern.slf4j.Slf4j;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.locks.InterProcessReadWriteLock;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.data.Stat;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;

import java.util.ArrayList;
import java.util.List;

@Slf4j
@Service
public class ZookeeperServiceImpl implements ZookeeperService {
    @Override
    public boolean isExistNode(String path) {
        CuratorFramework client = ZookeeperConfig.getClient();
        client.sync() ;
        try {
            Stat stat = client.checkExists().forPath(path);
            return client.checkExists().forPath(path) != null;
        } catch (Exception e) {
            log.error("isExistNode error...", e);
            e.printStackTrace();
        }
        return false;
    }
    @Override
    public void createNode(CreateMode mode, String path) {
        CuratorFramework client = ZookeeperConfig.getClient() ;
        try {
            // 递归创建所需父节点
            client.create().creatingParentsIfNeeded().withMode(mode).forPath(path);
        } catch (Exception e) {
            log.error("createNode error...", e);
            e.printStackTrace();
        }
    }
    @Override
    public void setNodeData(String path, String nodeData) {
        CuratorFramework client = ZookeeperConfig.getClient() ;
        try {
            // 设置节点数据
            client.setData().forPath(path, nodeData.getBytes("UTF-8"));
        } catch (Exception e) {
            log.error("setNodeData error...", e);
            e.printStackTrace();
        }
    }
    @Override
    public void createNodeAndData(CreateMode mode, String path, String nodeData) {
        CuratorFramework client = ZookeeperConfig.getClient() ;
        try {
            // 创建节点，关联数据
            client.create().creatingParentsIfNeeded().withMode(mode)
                  .forPath(path,nodeData.getBytes("UTF-8"));
        } catch (Exception e) {
            log.error("createNode error...", e);
            e.printStackTrace();
        }
    }
    @Override
    public String getNodeData(String path) {
        CuratorFramework client = ZookeeperConfig.getClient() ;
        try {
            // 数据读取和转换
            byte[] dataByte = client.getData().forPath(path) ;
            String data = new String(dataByte,"UTF-8") ;
            if (!StringUtils.isEmpty(data)){
                return data ;
            }
        }catch (Exception e) {
            log.error("getNodeData error...", e);
            e.printStackTrace();
        }
        return null;
    }
    @Override
    public List<String> getNodeChild(String path) {
        CuratorFramework client = ZookeeperConfig.getClient() ;
        List<String> nodeChildDataList = new ArrayList<>();
        try {
            // 节点下数据集
            nodeChildDataList = client.getChildren().forPath(path);
        } catch (Exception e) {
            log.error("getNodeChild error...", e);
            e.printStackTrace();
        }
        return nodeChildDataList;
    }
    @Override
    public void deleteNode(String path, Boolean recursive) {
        CuratorFramework client = ZookeeperConfig.getClient() ;
        try {
            if(recursive) {
                // 递归删除节点
                client.delete().guaranteed().deletingChildrenIfNeeded().forPath(path);
            } else {
                // 删除单个节点
                client.delete().guaranteed().forPath(path);
            }
        } catch (Exception e) {
            log.error("deleteNode error...", e);
            e.printStackTrace();
        }
    }
    @Override
    public InterProcessReadWriteLock getReadWriteLock(String path) {
        CuratorFramework client = ZookeeperConfig.getClient() ;
        // 写锁互斥、读写互斥
        InterProcessReadWriteLock readWriteLock = new InterProcessReadWriteLock(client, path);
        return readWriteLock ;
    }
}

Zookeeper操作Controller类

package com.example.zk.web;

import com.example.zk.service.ZookeeperService;
import org.apache.zookeeper.CreateMode;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

import static org.apache.zookeeper.CreateMode.PERSISTENT;

/**
 * Zookeeper操作
 * @author lanx
 * @date 2022/3/6
 */
@RestController
public class ZookeeperApi {
    @Autowired
    private ZookeeperService zookeeperService ;

    /**
     * 获取节点下数据
     * @param path
     * @return
     */
    @GetMapping("/getNodeData")
    public String getNodeData (String path) {
        return zookeeperService.getNodeData(path) ;
    }

    /**
     * 判断节点是否存在
     * @param path
     * @return
     */
    @GetMapping("/isExistNode")
    public boolean isExistNode (final String path){
        return zookeeperService.isExistNode(path) ;
    }

    /**
     * 创建节点
     * @param path
     * @return
     */
    @GetMapping("/createNode")
    public String createNode (String path ){
        zookeeperService.createNode(CreateMode.PERSISTENT,path) ;
        return "success" ;
    }

    /**
     * 节点设置数据
     * @param path
     * @param nodeData
     * @return
     */
    @GetMapping("/setNodeData")
    public String setNodeData (String path, String nodeData) {
        zookeeperService.setNodeData(path,nodeData) ;
        return "success" ;
    }

    /**
     * 创建节点并保存数据
     * @param path
     * @param nodeData
     * @return
     */
    @GetMapping("/createNodeAndData")
    public String createNodeAndData ( String path , String nodeData){
        zookeeperService.createNodeAndData(PERSISTENT,path,nodeData) ;
        return "success" ;
    }

    /**
     *获取节点下数据
     * @param path
     * @return
     */
    @GetMapping("/getNodeChild")
    public List<String> getNodeChild (String path) {
        return zookeeperService.getNodeChild(path) ;
    }

    /**
     * 是否递归删除节点
     * @param path
     * @param recursive
     * @return
     */
    @GetMapping("/deleteNode")
    public String deleteNode (String path,Boolean recursive) {
        zookeeperService.deleteNode(path,recursive) ;
        return "success" ;
    }
}

接口测试

http://127.0.0.1:8088/createNode?path=/llx/222