2.Zookeeper集成springboot操作节点，事件监听，分布式锁实现

1.Springboot项目中添加zookeeper 已经对应的客户端依赖 ，pom.xml文件如下

 <!-- Zookeeper组件 -->
        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>3.9.1</version>
        </dependency>
        <!-- 包含Curator组件 -->
        <dependency>
            <groupId>org.springframework.integration</groupId>
            <artifactId>spring-integration-zookeeper</artifactId>
            <version>6.2.2</version>
        </dependency>

2.application.yml 文件中配置zookeeper连接的相关配置信息

zookeeper:
  #服务器地址
  connectString: 127.0.0.1:2181
  #会话超时时间
  sessionTimeoutMs: 3000
  #连接超时时间
  connectionTimeoutMs: 60000
  #最大重试次数
  maxRetries: 3
  #初始休眠时间
  baseSleepTimeMs: 1000

3.java配置的方式添加zookeeper相关的配置

package com.jinyi.up.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.framework.recipes.locks.InterProcessMutex;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.annotation.PostConstruct;

/**
 * @author huangchong
 * @date 2024/3/5 20:48
 * @desc
 */
@Slf4j
@Configuration
public class ZookeeperConfig {

    @Value("${zookeeper.connectString}")
    private String connectString;

    @Value("${zookeeper.baseSleepTimeMs}")
    private int baseSleepTimeMs;

    @Value("${zookeeper.maxRetries}")
    private int maxRetries ;

    @Value("${zookeeper.connectionTimeoutMs}")
    int connectionTimeoutMs ;

    @Value("${zookeeper.sessionTimeoutMs}")
    int sessionTimeoutMs ;

    private static CuratorFramework client = null ;
    /**
     * 初始化
     */
    @PostConstruct
    public void init (){
        // 重试策略
        RetryPolicy policy = new ExponentialBackoffRetry(baseSleepTimeMs, maxRetries);
       //通过工厂创建Curator
        client = CuratorFrameworkFactory.builder()
                .connectString(connectString)
                .connectionTimeoutMs(connectionTimeoutMs)
                .sessionTimeoutMs(sessionTimeoutMs)
                .retryPolicy(policy).build();
        //开启连接
        client.start();
        log.info("zookeeper 初始化完成...");
    }

    @Bean
    public CuratorFramework getClient (){
        return client ;
    }

 /**
     * 分布式锁bean 注入spring管理中
     */
    @Bean
    public InterProcessMutex distributedLock() throws Exception {
        //使用了Curator提供的InterProcessMutex来创建一个分布式锁。我们使用ZooKeeper的路径/lock来表示锁的资源。
        InterProcessMutex distributedLock = new InterProcessMutex(client, "/lock");
        return distributedLock;
    }
}

4.Zookeeper基础操作服务和分布式锁服务编码

package com.jinyi.up.client.service;

import com.jinyi.up.zk.process.AbstractListenerProcess;
import lombok.extern.slf4j.Slf4j;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.cache.*;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.data.Stat;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.nio.charset.StandardCharsets;

/**
 * @author huangchong
 * @date 2024/3/5 21:39
 * @desc
 */
@Slf4j
@Service
public class ZookeeperService {

    @Resource
    private CuratorFramework client;

    /**
     * 查询节点数据
     *
     * @param nodePath 节点
     * @return {@link String}
     */
    public String queryData(String nodePath) {
        try {
            Stat stat = client.checkExists().forPath(nodePath);
            if (stat != null) {
                byte[] bytes = client.getData().forPath(nodePath);
                return new String(bytes, StandardCharsets.UTF_8);
            }
            return null;
        } catch (Exception e) {
            log.error("查询节点数据失败:", e);
            return null;
        }
    }

    /**
     * 创建节点
     *
     * @param mode     节点类型
     * @param nodePath 节点路径
     * @param nodeData 节点数据
     * @return {@link String}
     */
    public String create(CreateMode mode, String nodePath, String nodeData) {
        try {
            Stat stat = client.checkExists().forPath(nodePath);
            if (stat == null) {
                return client.create()
                        .withMode(mode)
                        .forPath(nodePath, nodeData.getBytes());
            } else {
                return null;
            }
        } catch (Exception e) {
            log.error("创建节点失败:", e);
            return null;
        }
    }


    /**
     * 更新节点数据
     *
     * @param nodePath 节点路径
     * @param nodeData 节点数据
     * @return {@link Stat}
     */
    public boolean update(String nodePath, String nodeData) {
        try {
            Stat stat = client.checkExists().forPath(nodePath);
            if (stat != null) {
                stat = client.setData().forPath(nodePath, nodeData.getBytes());
            }
            return stat != null;
        } catch (Exception e) {
            log.error("更新节点失败:", e);
            return false;
        }
    }

    /**
     * 删除节点
     *
     * @param nodePath v
     * @return {@link boolean}
     */
    public boolean delete(String nodePath) {
        try {
            Stat stat = client.checkExists().forPath(nodePath);
            if (stat != null) {
                client.delete().forPath(nodePath);
            }
            return true;
        } catch (Exception e) {
            log.error("删除节点失败:", e);
            return false;
        }

    }

    /**
     * 监听一个节点
     *
     * @param nodePath 被监听节点路径
     * @return {@link }
     */
    public boolean addWatchNodeListener(String nodePath) {
        CuratorCache curatorCache = CuratorCache.builder(client, nodePath).build();
        CuratorCacheListener listener = CuratorCacheListener.builder()
                .forNodeCache(new NodeCacheListener() {
                    @Override
                    public void nodeChanged() throws Exception {
                        log.info("监听到节点变动");
                        //TODO
                    }
                }).build();
        curatorCache.listenable().addListener(listener);
        curatorCache.start();
        return true;
    }


    /**
     * 监听子孙节点 支持子节点的子节点监听
     * TreeCache监听节点自己和所有子节点们
     *
     * @param nodePath  被监听节点路径
     * @param processer 监听后处理
     * @return {@link }
     */
    public boolean addWatchTreeListener(String nodePath, AbstractListenerProcess processer) {
        CuratorCache curatorCache = CuratorCache.builder(client, nodePath).build();
        CuratorCacheListener listener = CuratorCacheListener.builder()
                .forTreeCache(client, new TreeCacheListener() {
                    @Override
                    public void childEvent(CuratorFramework curatorFramework, TreeCacheEvent treeCacheEvent) {
                        log.info("监听到子节点变动,变动类型:{}", treeCacheEvent.getType().toString());
                        processer.process(curatorFramework, treeCacheEvent);
                    }
                }).build();
        curatorCache.listenable().addListener(listener);
        curatorCache.start();
        return true;
    }
}

package com.jinyi.up.zk.service;

import com.jinyi.up.zk.process.AbstractListenerProcess;
import lombok.extern.slf4j.Slf4j;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.cache.*;
import org.apache.curator.framework.recipes.locks.InterProcessMutex;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.data.Stat;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.nio.charset.StandardCharsets;

/**
 * @author huangchong
 * @date 2024/3/5 21:39
 * @desc
 */
@Slf4j
@Service
public class ZookeeperLockService {
    @Resource
    private InterProcessMutex distributedLock;

    public void doProtectedOperation() throws Exception {
        //acquire()方法获取锁
        distributedLock.acquire();
        try {
            // 执行需要保护的代码块
        } finally {
            distributedLock.release();
        }
    }
}

5.watcher机制事件处理抽象封装

package com.jinyi.up.zk.process;

import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent;
import org.apache.curator.framework.recipes.cache.TreeCacheEvent;

/**
 * @author huangchong
 * @date 2024/3/5 21:58
 * @desc
 */
public abstract class AbstractListenerProcess {

    /**
     * 处理监听节点自己和所有子节点们变更事件
     *
     * @param client       zk客户端
     * @param event 子节点事件
     * @return {@link }
     */
    public abstract void process(CuratorFramework client, TreeCacheEvent event);
}

package com.jinyi.up.zk.process;

import lombok.extern.slf4j.Slf4j;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.cache.TreeCacheEvent;

/**
 * @author huangchong
 * @date 2024/3/5 21:58
 * @desc
 */
@Slf4j
public  class WatcherTreeListenerProcess extends AbstractListenerProcess{
    /**
     * 实际处理监听节点自己和所有子节点们变更事件
     *
     * @param client zk客户端
     * @param event 子节点事件
     * @return {@link }
     */
    @Override
    public void process(CuratorFramework client, TreeCacheEvent event) {
        //事件path
        String path = event.getData().getPath();
        switch (event.getType()) {
            case NODE_ADDED:
                log.info("新增子节点：" + path);
                break;

            case NODE_UPDATED:
                log.info("更新子节点：" + path);
                break;

            case NODE_REMOVED:
                log.info("删除子节点：" + path);
                break;

            default:
                break;
        }
    }
}

6.基本操作的单元测试代码文章来源地址https://www.toymoban.com/news/detail-838216.html

package com.jinyi.zookeeper;

import com.jinyi.up.zk.ZookeeperApplication;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
///此处classes内的内容是@SpringBootApplication入口
@SpringBootTest(classes = {ZookeeperApplication.class})
public abstract class BaseZkBootTest {
}

package com.jinyi.zookeeper;

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.junit.Test;


import javax.annotation.Resource;
import java.nio.charset.StandardCharsets;

/**
 * @author huangchong
 * @date 2024/3/5 21:00
 * @desc
 */
@Slf4j
public class ZookeeperBaseTest extends BaseZkBootTest {
    @Resource
    private CuratorFramework client;

    @Test
    public void testAddPersistentNode() throws Exception {
        // 创建一个持久化节点/persistent_node，断开连接时不会自动删除
        client.create()
                .creatingParentsIfNeeded()
                .withMode(CreateMode.PERSISTENT)
                .forPath("/persistent_node");
    }

    @Test
    public void testZnodeExists() throws Exception {
        // 判断节点是否存在，persistent_node2不存在所以stat2是null
        Stat stat = client.checkExists().forPath("/persistent_node");
        log.info(String.valueOf(stat));
        Stat stat2 = client.checkExists().forPath("/persistent_node2");
        log.info(String.valueOf(stat2));
    }


    @Test
    public void testSetData() throws Exception {
        // 设置节点数据
        client.setData()
                .forPath("/persistent_node", "persistent_node_data".getBytes(StandardCharsets.UTF_8));
    }

    @Test
    public void testCreateAndSet() throws Exception {
        // 创建一个持久化节点并设置节点数据
        client.create().creatingParentsIfNeeded().withMode(CreateMode.PERSISTENT)
                .forPath("//persistent_node1", "persistent_node_data1".getBytes(StandardCharsets.UTF_8));
    }

    @Test
    public void testGetData() throws Exception {
        // 查询节点数据
        byte[] data = client.getData().forPath("/persistent_node1");
        log.info(new String(data, StandardCharsets.UTF_8));
    }

    @Test
    public void testDelete() throws Exception {
        // 删除节点
        client.delete()
                .guaranteed()
                .deletingChildrenIfNeeded()
                .forPath("/persistent_node1");
    }

    @Test
    public void testReadLock() throws Exception {
        // 读写锁-读
        InterProcessReadWriteLock lock = new InterProcessReadWriteLock(client, "/lock-read");
        lock.readLock().acquire();
        log.info("获取-ReadLock");
        lock.readLock().release();
    }

    @Test
    public void testWriteLock() throws Exception {
        // 读写锁-写
        InterProcessReadWriteLock lock = new InterProcessReadWriteLock(client, "/lock-write");
        lock.writeLock().acquire();
        log.info("获取-WriteLock");
        lock.writeLock().release();
    }
}

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