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zookeeper代码实现常用命令 - 雨中散步撒哈拉
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作者：雨中散步撒哈拉
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公众号：雨中散步撒哈拉
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环境说明:
- 服务器为centos7集群
- zk为zookeeper-3.4.10.tar.gz版本
- jdk为1.8
一、创建项目
1. 添加依赖包，pom文件如下
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>RELEASE</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.8.2</version>
</dependency>
<!--
https://mvnrepository.com/artifact/org.apache.zookeeper/zook
eeper -->
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.4.10</version>
</dependency>
</dependencies>
2. 配置日志文件
资源文件创建日志配置文件log4j.properties
log4j.rootLogger=INFO, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n
log4j.appender.logfile=org.apache.log4j.FileAppender
log4j.appender.logfile.File=target/spring.log
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n
二、代码实现zk命令
0. 创建连接
连接集群ip和对外端口2181，集群映射，已在windows做了配置
hosts文件内容：
代码实现连接:
private static final String IPS = "master:2181,slave1:2181,slave2:2181";
private static final int SESSIONTIMEOUT = 200;
private ZooKeeper zkClient = null;
@Test
public void contectTest() throws Exception{
zkClient = new ZooKeeper(IPS, SESSIONTIMEOUT, new Watcher() {
@Override
public void process(WatchedEvent event) {
}
});
System.out.println("==================");
System.out.println(zkClient.getState());
System.out.println("==================");
}
运行打印结果
image.png
2. 创建节点
创建/idea节点，类型为临时节点
private static final String IPS = "master:2181,slave1:2181,slave2:2181";
private static final int SESSIONTIMEOUT = 200;
private ZooKeeper zkClient = null;
@Before
public void contectTest() throws Exception{
zkClient = new ZooKeeper(IPS, SESSIONTIMEOUT, new Watcher() {
@Override
public void process(WatchedEvent event) {
}
});
System.out.println("==================");
System.out.println(zkClient.getState());
System.out.println("==================");
}
@Test
public void createTest() throws Exception{
String s = zkClient.create("/idea", "helloworld".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);
System.out.println(s);
}
image.png
3. 监听节点变化
监控根节点下的子节点变化
private static final String IPS = "master:2181,slave1:2181,slave2:2181";
private static final int SESSIONTIMEOUT = 200;
private ZooKeeper zkClient = null;
@Before
public void contectTest() throws Exception{
zkClient = new ZooKeeper(IPS, SESSIONTIMEOUT, new Watcher() {
@Override
public void process(WatchedEvent event) {
System.out.println(event.getType() + "--" + event.getPath());
try {
zkClient.getChildren("/", true);
} catch (KeeperException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
System.out.println("==================");
System.out.println(zkClient.getState());
System.out.println("==================");
}
@Test
public void childrenTest() throws Exception{
List<String> children = zkClient.getChildren("/", true);
for (String ch : children){
System.out.println(ch);
}
Thread.sleep(Long.MAX_VALUE);
}
在xshell模范添加节点，也可以在代码中模仿添加节点
[zk: localhost:2181(CONNECTED) 0] create -e /java "java"
Created /java
[zk: localhost:2181(CONNECTED) 1] create -e /python "java"
Created /python
image.png
4. 判断节点是否存在
private static final String IPS = "master:2181,slave1:2181,slave2:2181";
private static final int SESSIONTIMEOUT = 200;
private ZooKeeper zkClient = null;
@Before
public void contectTest() throws Exception{
zkClient = new ZooKeeper(IPS, SESSIONTIMEOUT, new Watcher() {
@Override
public void process(WatchedEvent event) {
}
});
System.out.println("==================");
System.out.println(zkClient.getState());
System.out.println("==================");
}
@Test
public void exTest() throws Exception{
Stat exists = zkClient.exists("/test", false);
System.out.println(exists == null ? "no" : "yes");
}
image.png
5. 测试完整代码
package com.example.demo;
import org.apache.zookeeper.*;
import org.apache.zookeeper.data.Stat;
import org.junit.Before;
import org.junit.Test;
import java.util.List;
public class ZKDemo {
private static final String IPS = "master:2181,slave1:2181,slave2:2181";
private static final int SESSIONTIMEOUT = 200;
private ZooKeeper zkClient = null;
@Before
public void contectTest() throws Exception{
zkClient = new ZooKeeper(IPS, SESSIONTIMEOUT, new Watcher() {
@Override
public void process(WatchedEvent event) {
/*System.out.println(event.getType() + "--" + event.getPath());
try {
zkClient.getChildren("/", true);
} catch (KeeperException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}*/
}
});
System.out.println("==================");
System.out.println(zkClient.getState());
System.out.println("==================");
}
@Test
public void createTest() throws Exception{
String s = zkClient.create("/idea", "helloworld".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);
System.out.println(s);
}
@Test
public void childrenTest() throws Exception{
List<String> children = zkClient.getChildren("/", true);
for (String ch : children){
System.out.println(ch);
}
Thread.sleep(Long.MAX_VALUE);
}
@Test
public void exTest() throws Exception{
Stat exists = zkClient.exists("/test", false);
System.out.println(exists == null ? "no" : "yes");
}
}
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