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/47Gamer/p/13789058.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
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：47
* 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：47
* @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：47
* @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：47
* @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：47
* @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：47
* @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：47
* @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：47
* @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
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：47
*/
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();
}
}
