java springboot整合zookeeper入门教程（增删改查）

java springboot整合zookeeper增删改查入门教程

zookeeper的安装与集群搭建参考：https://www.cnblogs.com/zwcry/p/10272506.html

描述：本章主要讲java代码如何实现zookeeper节点的增删改查，用法与解释全部在注释里。

　　　本教程的工程，使用maven、jdk8、springboot、zookeeper 3.4.12

　　　重点：大家学会增删改查后，不妨动脑想下，zookeeper如何实现分布式锁，小小的提示下，竞争创建临时节点，创建成功者，则获得锁。

　　　注：请注意log4j2的配置，因为是java测试，并没有通过web、servlet启动程序，所以请把log4j2放在资源目录的根目录，我是新建了一个资源目录包log4j，将log4j2.xml放在该目录下。

1、pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.1.RELEASE</version>
    </parent>
    
    <groupId>com.qy.code</groupId>
    <artifactId>qy-zk</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>pom</packaging>
    
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <maven.compiler.compilerVersion>1.8</maven.compiler.compilerVersion>
        <maven.test.skip>true</maven.test.skip>
        <java.version>1.8</java.version>
        <spring.boot.version>2.0.1.RELEASE</spring.boot.version>
        <qy.code.version>0.0.1-SNAPSHOT</qy.code.version>
    </properties>
    
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
            <!-- 不使用springboot默认log -->
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-logging</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-log4j2</artifactId>
        </dependency>
        
        <!-- https://mvnrepository.com/artifact/org.apache.zookeeper/zookeeper -->
        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>3.4.12</version>
            <!-- 排除冲突jar -->
            <exclusions>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        
    </dependencies>
    
    <repositories>
        <repository>
            <id>nexus-aliyun</id>
            <name>Nexus aliyun</name>
            <url>http://maven.aliyun.com/nexus/content/groups/public</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>nexus-aliyun</id>
            <name>Nexus aliyun</name>
            <url>http://maven.aliyun.com/nexus/content/groups/public</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>
    
    
    <build>
        <plugins>
            <!-- 要将源码放上去，需要加入这个插件 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-source-plugin</artifactId>
                <configuration>
                    <attach>true</attach>
                </configuration>
                <executions>
                    <execution>
                        <phase>compile</phase>
                        <goals>
                            <goal>jar</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

2.log4j2.xml

注：请注意log4j2的配置，因为是java测试，并没有通过web、servlet启动程序，所以请把log4j2放在资源目录的根目录，我是新建了一个资源目录包log4j，将log4j2.xml放在该目录下。

<?xml version="1.0" encoding="UTF-8"?>
<!-- log4j2 本身日志打印级别，以及重新刷新配置文件的时间-->
<Configuration status="WARN" monitorInterval="5">
    <Properties>
        <Property name="log-path">logs</Property>
        <Property name="log-file-temp">temp.log</Property>
        <Property name="log-file-info">info.log</Property>
        <Property name="log-file-warn">warn.log</Property>
        <Property name="log-file-error">error.log</Property>
        <!-- 输出格式 -->
        <!-- <Property name="pattern">%p [%date{yyyy-MM-dd HH:mm:ss,SSS}] [%thread] %l %m %n </Property> -->
        <Property name="pattern">%m %n </Property>
        <!-- 日志切割的最小单位 -->
        <property name="every_file_size">1M</property>
    </Properties>
    <Appenders>
        <!-- 重置太打印 打印debug及以上级别 -->
        <Console name="Console-Appender" target="SYSTEM_OUT">
            <ThresholdFilter level="DEBUG" onMatch="ACCEPT" onMismatch="DENY" />
            <PatternLayout pattern="${pattern}"/>
        </Console>
        
           <!--文件会打印出所有信息，这个log每次运行程序会自动清空，由append属性决定，这个也挺有用的，适合临时测试用-->
        <File name="RollingFile-Appender-Temp" fileName="${log-path}/${log-file-temp}" append="false">
            <PatternLayout pattern="${pattern}"/>
        </File> 
        <!-- 这个会打印出所有的信息，每次大小超过size，则这size大小的日志会自动存入按年份-月份建立的文件夹下面并进行压缩，作为存档-->
        <RollingFile name="RollingFile-Appender-INFO" fileName="${log-path}/${log-file-info}" append="true"
                     filePattern="${log-path}/$${date:yyyy-MM}/info-%d{yyyy-MM-dd}-%i.log">
            <!-- 只输出INFO级别 -->
            <Filters>
                <ThresholdFilter level="INFO" onMatch="ACCEPT" onMismatch="DENY" />
                <ThresholdFilter level="WARN" onMatch="DENY" onMismatch="NEUTRAL" />
                <ThresholdFilter level="ERROR" onMatch="DENY" onMismatch="NEUTRAL" />
            </Filters>
            <PatternLayout pattern="${pattern}" />
            <SizeBasedTriggeringPolicy size="${every_file_size}"/>
            <!-- DefaultRolloverStrategy属性如不设置，则默认为最多同一文件夹下7个文件，这里设置了10 -->
            <DefaultRolloverStrategy max="10"/>
        </RollingFile>
        <RollingFile name="RollingFile-Appender-WARN" fileName="${log-path}/${log-file-warn}" append="true"
                     filePattern="${log-path}/$${date:yyyy-MM}/warn-%d{yyyy-MM-dd}-%i.log">
            <!-- 只输出Warn级别 -->
            <Filters>
                <ThresholdFilter level="WARN" onMatch="ACCEPT" onMismatch="DENY" />
                <ThresholdFilter level="ERROR" onMatch="DENY" onMismatch="NEUTRAL" />
            </Filters>
            <PatternLayout pattern="${pattern}" />
            <SizeBasedTriggeringPolicy size="${every_file_size}"/>
            <!-- DefaultRolloverStrategy属性如不设置，则默认为最多同一文件夹下7个文件，这里设置了10 -->
            <DefaultRolloverStrategy max="10"/>
        </RollingFile>
        <RollingFile name="RollingFile-Appender-ERROR" fileName="${log-path}/${log-file-error}" append="true"
                     filePattern="${log-path}/$${date:yyyy-MM}/error-%d{yyyy-MM-dd}-%i.log">
            <!-- 只输出ERROR级别 -->
            <Filters>
                <ThresholdFilter level="ERROR" onMatch="ACCEPT" onMismatch="DENY" />
            </Filters>
            <PatternLayout pattern="${pattern}" />
            <SizeBasedTriggeringPolicy size="${every_file_size}"/>
            <!-- DefaultRolloverStrategy属性如不设置，则默认为最多同一文件夹下7个文件，这里设置了10 -->
            <DefaultRolloverStrategy max="10"/>
        </RollingFile>
    </Appenders>
    <Loggers>
        <logger name="java.sql" level="debug" additivity="false">
            <appender-ref ref="Console-Appender"/>
        </logger>
        <logger name="com.ibatis" level="debug" additivity="false">
            <appender-ref ref="Console-Appender"/>
        </logger>
        <!-- 第三方的软件日志级别 -->
        <logger name="org.springframework" level="info" additivity="true">
            <AppenderRef ref="RollingFile-Appender-WARN" />
            <AppenderRef ref="RollingFile-Appender-ERROR" />
        </logger>
        <!-- 第三方的软件日志级别 -->
        <logger name="org.apache" level="warn" additivity="true">
            <AppenderRef ref="RollingFile-Appender-WARN" />
            <AppenderRef ref="RollingFile-Appender-ERROR" />
        </logger>
        <!-- 异步输出 -->
        <Root level="INFO">
            <AppenderRef ref="Console-Appender"/>
            <AppenderRef ref="RollingFile-Appender-Temp"/>
            <AppenderRef ref="RollingFile-Appender-INFO" />
            <AppenderRef ref="RollingFile-Appender-WARN" />
            <AppenderRef ref="RollingFile-Appender-ERROR" />
        </Root>
    </Loggers>
</Configuration>

3.增删改查.java

package com.qy.zk;

import java.io.IOException;
import java.util.List;
import java.util.concurrent.CountDownLatch;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.ACL;
import org.apache.zookeeper.data.Stat;

/**
 * 描述：zookeeper增删改查
 * 作者：七脉
 * 重点：删除、修改、查询所用的version版本号，分布式事务锁的实现方式，乐观锁。ACL权限：所有人、限定人、限定IP等
 */
public class MyZkConnect{
    
    private static  Logger log=LogManager.getLogger(MyZkConnect.class);
    
    //集群节点
    public static final String zkServerClusterConnect = "192.168.159.129:2181,192.168.159.129:2182,192.168.159.129:2183";
    
    //单一节点
    public static final String zkServerSingleConnect = "192.168.159.129:2181";
    
    //超时毫秒数
    public static final int timeout = 3000;
    
    public static void main(String[] args) throws InterruptedException, IOException, KeeperException {
        //建立连接
        ZooKeeper zk = connect();
        //zk.close();//关闭后不支持重连
        log.info("zk 状态："+zk.getState());
        
        /**恢复会话连接**/
        //long sessionId = zk.getSessionId();
        //byte[] sessionPasswd = zk.getSessionPasswd();
        //zk2会话重连后，zk会话将失效，不再支持做增删改查操作。
        //ZooKeeper zk2 = reconnect(sessionId, sessionPasswd);
        
        /**创建节点**/
        //create(zk, "/myzk", "myzk");
        
        /**查询节点Data**/
        queryData(zk, "/myzk");
        
        /**修改节点data**/
        //update(zk, "/myzk", "myzk-update");
        
        /**删除节点**/
        //delete(zk, "/myzk");
    }
        
    
    /**
     * 描述：建立连接
     * 作者：七脉
     * @return
     * @throws IOException
     * @throws InterruptedException
     */
    public static ZooKeeper connect() throws IOException, InterruptedException{
        CountDownLatch cdl = new CountDownLatch(1);
        log.info("准备建立zk服务");
        ZooKeeper zk = new ZooKeeper(zkServerClusterConnect, timeout, new MyZkWatcher(cdl,"建立连接"));
        log.info("完成建立zk服务");
        cdl.await();//这里为了等待wather监听事件结束
        return zk;
    }
    
    /**
     * 描述：重新连接服务
     * 作者：七脉
     * @param sessionId 现有会话ID
     * @param sessionPasswd 现有会话密码
     * @return
     * @throws IOException
     * @throws InterruptedException
     * 重点：关闭后的会话连接，不支持重连。重连后，前会话连接将会失效。
     */
    public static ZooKeeper reconnect(long sessionId, byte[] sessionPasswd) throws IOException, InterruptedException{
        CountDownLatch cdl = new CountDownLatch(1);
        log.info("准备重新连接zk服务");
        ZooKeeper zk = new ZooKeeper(zkServerClusterConnect, timeout, new MyZkWatcher(cdl,"重新连接"), sessionId, sessionPasswd);
        log.info("完成重新连接zk服务");
        cdl.await();//这里为了等待wather监听事件结束
        return zk;
    }
    
    /**
     * 描述：创建节点
     * 作者：七脉
     * @param zk
     * @param nodePath
     * @param nodeData
     * @throws KeeperException
     * @throws InterruptedException
     */
    public static void create(ZooKeeper zk,String nodePath,String nodeData) throws KeeperException, InterruptedException{
        log.info("开始创建节点：{}， 数据：{}",nodePath,nodeData);
        List<ACL> acl = Ids.OPEN_ACL_UNSAFE;
        CreateMode createMode = CreateMode.PERSISTENT;
        String result = zk.create(nodePath, nodeData.getBytes(), acl, createMode);
        //创建节点有两种，上面是第一种，还有一种可以使用回调函数及参数传递，与上面方法名称相同。
        log.info("创建节点返回结果：{}",result);
        log.info("完成创建节点：{}， 数据：{}",nodePath,nodeData);
    }
    
    /**
     * 描述：查询节点结构信息
     * 作者：七脉
     * @param zk
     * @param nodePath
     * @return
     * @throws KeeperException
     * @throws InterruptedException
     */
    public static Stat queryStat(ZooKeeper zk,String nodePath) throws KeeperException, InterruptedException{
        log.info("准备查询节点Stat，path：{}", nodePath);
        Stat stat = zk.exists(nodePath, false);
        log.info("结束查询节点Stat，path：{}，version：{}", nodePath, stat.getVersion());
        return stat;
    }
    
    /**
     * 描述：查询节点Data值信息
     * 作者：七脉
     * @param zk
     * @param nodePath
     * @return
     * @throws KeeperException
     * @throws InterruptedException
     */
    public static String queryData(ZooKeeper zk,String nodePath) throws KeeperException, InterruptedException{
        log.info("准备查询节点Data,path：{}", nodePath);
        String data = new String(zk.getData(nodePath, false, queryStat(zk, nodePath)));
        log.info("结束查询节点Data,path：{}，Data：{}", nodePath, data);
        return data;
    }
    
    
    /**
     * 描述：修改节点
     * 作者：七脉
     * @param zk
     * @param nodePath
     * @param nodeData
     * @throws KeeperException
     * @throws InterruptedException
     * 重点：每次修改节点的version版本号都会变更，所以每次修改都需要传递节点原版本号，以确保数据的安全性。
     */
    public static Stat update(ZooKeeper zk,String nodePath,String nodeData) throws KeeperException, InterruptedException{
        //修改节点前先查询该节点信息
        Stat stat = queryStat(zk, nodePath);
        log.info("准备修改节点，path：{}，data：{}，原version：{}", nodePath, nodeData, stat.getVersion());
        Stat newStat = zk.setData(nodePath, nodeData.getBytes(), stat.getVersion());
        //修改节点值有两种方法，上面是第一种，还有一种可以使用回调函数及参数传递，与上面方法名称相同。
        //zk.setData(path, data, version, cb, ctx);
        log.info("完成修改节点，path：{}，data：{}，现version：{}", nodePath, nodeData, newStat.getVersion());
        return stat;
    }
    
    /**
     * 描述：删除节点
     * 作者：七脉
     * @param zk
     * @param nodePath
     * @throws InterruptedException
     * @throws KeeperException
     */
    public static void delete(ZooKeeper zk,String nodePath) throws InterruptedException, KeeperException{
        //删除节点前先查询该节点信息
        Stat stat = queryStat(zk, nodePath);
        log.info("准备删除节点，path：{}，原version：{}", nodePath, stat.getVersion());
        zk.delete(nodePath, stat.getVersion());
        //修改节点值有两种方法，上面是第一种，还有一种可以使用回调函数及参数传递，与上面方法名称相同。
        //zk.delete(path, version, cb, ctx);
        log.info("完成删除节点，path：{}", nodePath);
    }
}

4.watcher观察者.java

package com.qy.zk;

import java.util.concurrent.CountDownLatch;

import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 描述：ZK服务观察者事件
 * 作者：七脉
 */
public class MyZkWatcher implements Watcher{
    
    private static final Logger log = LoggerFactory.getLogger(MyZkWatcher.class);
    
    //异步锁
    private CountDownLatch cdl;
    
    //标记
    private String mark;
    
    public MyZkWatcher(CountDownLatch cdl,String mark) {
        this.cdl = cdl;
        this.mark = mark;
    }

    //监听事件处理方法
    public void process(WatchedEvent event) {
        log.info(mark+" watcher监听事件：{}",event);
        cdl.countDown();
    }

}

本章节用到了CountDownLatch，不会的可以学下https://www.cnblogs.com/zwcry/p/9662499.html

源码：https://pan.baidu.com/s/1nWQvN9l2SsGupY6LPP0gTg