Hadoop生态圈-zookeeper的API用法详解
作者：尹正杰
版权声明：原创作品，谢绝转载！否则将追究法律责任。
一.测试前准备
1>.开启集群
[yinzhengjie@s101 ~]$ more `which xzk.sh`
#!/bin/bash
#@author :yinzhengjie
#blog:http://www.cnblogs.com/yinzhengjie
#EMAIL:y1053419035@qq.com#判断用户是否传参
if [ $# -ne ];then
echo "无效参数，用法为: $0 {start|stop|restart|status}"
exit
fi#获取用户输入的命令
cmd=$#定义函数功能
function zookeeperManger(){
case $cmd in
start)
echo "启动服务"
remoteExecution start
;;
stop)
echo "停止服务"
remoteExecution stop
;;
restart)
echo "重启服务"
remoteExecution restart
;;
status)
echo "查看状态"
remoteExecution status
;;
*)
echo "无效参数，用法为: $0 {start|stop|restart|status}"
;;
esac
}#定义执行的命令
function remoteExecution(){
for (( i= ; i<= ; i++ )) ; do
tput setaf
echo ========== s$i zkServer.sh $ ================
tput setaf
ssh s$i "source /etc/profile ; zkServer.sh $1"
done
}#调用函数
zookeeperManger
[yinzhengjie@s101 ~]$
[yinzhengjie@s101 ~]$ xzk.sh start
启动服务
========== s102 zkServer.sh start ================
ZooKeeper JMX enabled by default
Using config: /soft/zk/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
========== s103 zkServer.sh start ================
ZooKeeper JMX enabled by default
Using config: /soft/zk/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
========== s104 zkServer.sh start ================
ZooKeeper JMX enabled by default
Using config: /soft/zk/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[yinzhengjie@s101 ~]$ xcall.sh jps
============= s101 jps ============
Jps
命令执行成功
============= s102 jps ============
Jps
QuorumPeerMain
命令执行成功
============= s103 jps ============
Jps
QuorumPeerMain
命令执行成功
============= s104 jps ============
Jps
QuorumPeerMain
命令执行成功
============= s105 jps ============
Jps
命令执行成功
[yinzhengjie@s101 ~]$
[yinzhengjie@s101 ~]$ xzk.sh start
[yinzhengjie@s101 ~]$ start-dfs.sh
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/soft/hadoop-2.7./share/hadoop/common/lib/slf4j-log4j12-1.7..jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/soft/apache-hive-2.1.-bin/lib/log4j-slf4j-impl-2.4..jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
Starting namenodes on [s101 s105]
s101: starting namenode, logging to /soft/hadoop-2.7./logs/hadoop-yinzhengjie-namenode-s101.out
s105: starting namenode, logging to /soft/hadoop-2.7./logs/hadoop-yinzhengjie-namenode-s105.out
s103: starting datanode, logging to /soft/hadoop-2.7./logs/hadoop-yinzhengjie-datanode-s103.out
s102: starting datanode, logging to /soft/hadoop-2.7./logs/hadoop-yinzhengjie-datanode-s102.out
s105: starting datanode, logging to /soft/hadoop-2.7./logs/hadoop-yinzhengjie-datanode-s105.out
s104: starting datanode, logging to /soft/hadoop-2.7./logs/hadoop-yinzhengjie-datanode-s104.out
Starting journal nodes [s102 s103 s104]
s102: starting journalnode, logging to /soft/hadoop-2.7./logs/hadoop-yinzhengjie-journalnode-s102.out
s103: starting journalnode, logging to /soft/hadoop-2.7./logs/hadoop-yinzhengjie-journalnode-s103.out
s104: starting journalnode, logging to /soft/hadoop-2.7./logs/hadoop-yinzhengjie-journalnode-s104.out
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/soft/hadoop-2.7./share/hadoop/common/lib/slf4j-log4j12-1.7..jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/soft/apache-hive-2.1.-bin/lib/log4j-slf4j-impl-2.4..jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
Starting ZK Failover Controllers on NN hosts [s101 s105]
s101: starting zkfc, logging to /soft/hadoop-2.7./logs/hadoop-yinzhengjie-zkfc-s101.out
s105: starting zkfc, logging to /soft/hadoop-2.7./logs/hadoop-yinzhengjie-zkfc-s105.out
[yinzhengjie@s101 ~]$
[yinzhengjie@s101 ~]$ xcall.sh jps
============= s101 jps ============
Jps
DFSZKFailoverController
命令执行成功
============= s102 jps ============
Jps
DataNode
QuorumPeerMain
JournalNode
命令执行成功
============= s103 jps ============
DataNode
JournalNode
Jps
QuorumPeerMain
命令执行成功
============= s104 jps ============
JournalNode
Jps
DataNode
QuorumPeerMain
命令执行成功
============= s105 jps ============
DFSZKFailoverController
DataNode
Jps
命令执行成功
[yinzhengjie@s101 ~]$
[yinzhengjie@s101 ~]$ start-dfs.sh
2>.添加Maven依赖
<?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>
<groupId>cn.org.yinzhengjie</groupId>
<artifactId>MyZookeep</artifactId>
<version>1.0-SNAPSHOT</version> <dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency> <dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.4.6</version>
</dependency>
</dependencies>
</project>
二.Zookeeper的API常用方法介绍
1>.测试ls命令
/*
@author :yinzhengjie
Blog:http://www.cnblogs.com/yinzhengjie/tag/Hadoop%E7%94%9F%E6%80%81%E5%9C%88/
EMAIL:y1053419035@qq.com
*/
package cn.org.yinzhengjie.zookeeper; import org.apache.zookeeper.ZooKeeper;
import org.junit.Test;
import java.util.List; public class ZookeeperDemo {
/**
* 测试ls
*/
@Test
public void testList() throws Exception {
//定义连接服务器的URL，这些主机都在“C:\Windows\System32\drivers\etc\HOSTS”中做的有映射哟！
String conn = "s102:2181,s103:2181,s104:2181";
//实例化zk对象
//参数一：连接串，指定zk客户端地址；参数二：超时时间，超过此时间未获得连接，抛出异常；参数三：指定watcher对象，我们指定为null即可
ZooKeeper zk = new ZooKeeper(conn, 5000, null);
//我们查看“/”节点下的数据
List<String> children = zk.getChildren("/", null);
//将查询的结果进行遍历
for (String child : children) {
System.out.println(child);
}
}
}
以上代码输出结果如下：
2>.获取数据
/*
@author :yinzhengjie
Blog:http://www.cnblogs.com/yinzhengjie/tag/Hadoop%E7%94%9F%E6%80%81%E5%9C%88/
EMAIL:y1053419035@qq.com
*/
package cn.org.yinzhengjie.zookeeper; import org.apache.zookeeper.ZooKeeper;
import org.junit.Test; public class ZookeeperDemo {
/**
* 获取数据
*/
@Test
public void testGet() throws Exception {
//定义连接服务器的URL，这些主机都在“C:\Windows\System32\drivers\etc\HOSTS”中做的有映射哟！
String conn = "s102:2181,s103:2181,s104:2181"; //实例化zk对象
//参数一：连接串，指定zk客户端地址；参数二：超时时间，超过此时间未获得连接，抛出异常；参数三：指定watcher对象，我们指定为null即可
ZooKeeper zk = new ZooKeeper(conn, 5000, null);
byte[] data = zk.getData("/a", null, null);
zk.close();
System.out.println(new String(data));
}
}
以上代码输出结果如下：
3>.创建节点+数据
/*
@author :yinzhengjie
Blog:http://www.cnblogs.com/yinzhengjie/tag/Hadoop%E7%94%9F%E6%80%81%E5%9C%88/
EMAIL:y1053419035@qq.com
*/
package cn.org.yinzhengjie.zookeeper; import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.ZooKeeper;
import org.junit.Test; public class ZookeeperDemo {
/**
* 创建节点+数据
*/
@Test
public void testCreate() throws Exception {
//定义连接服务器的URL，这些主机都在“C:\Windows\System32\drivers\etc\HOSTS”中做的有映射哟！
String conn = "s102:2181,s103:2181,s104:2181";
//实例化zk对象
//参数一：连接串，指定zk客户端地址；参数二：超时时间，超过此时间未获得连接，抛出异常；参数三：指定watcher对象，我们指定为null即可
ZooKeeper zk = new ZooKeeper(conn, 5000, null);
//创建一个"/yzj"节点(该节点不能再zookeeper集群中存在，否则会抛异常哟)，并起名为“yinzhengjie”(写入的数据)。
String s = zk.create("/yzj", "yinzhengjie".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
System.out.println(s);
zk.close();
}
}
以上代码输出结果如下：
4>.删除节点
/*
@author :yinzhengjie
Blog:http://www.cnblogs.com/yinzhengjie/tag/Hadoop%E7%94%9F%E6%80%81%E5%9C%88/
EMAIL:y1053419035@qq.com
*/
package cn.org.yinzhengjie.zookeeper; import org.apache.zookeeper.ZooKeeper;
import org.junit.Test; public class ZookeeperDemo {
/**
* 删除节点
*/
@Test
public void testDelete() throws Exception {
String conn = "s102:2181,s103:2181,s104:2181";
//实例化zk对象
//param1：连接串，指定zk客户端地址；param2：超时时间，超过此时间未获得连接，抛出异常
ZooKeeper zk = new ZooKeeper(conn, 5000, null);
//删除zookeeper集群中的节点，删除的节点必须存在，如果不存在会抛异常哟（KeeperException$NoNodeException）
zk.delete("/yzj",-1);
zk.close();
}
}
5>.观察者模式，监控某个子节点小案例
/*
@author :yinzhengjie
Blog:http://www.cnblogs.com/yinzhengjie/tag/Hadoop%E7%94%9F%E6%80%81%E5%9C%88/
EMAIL:y1053419035@qq.com
*/
package cn.org.yinzhengjie.zookeeper; import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.junit.Test; public class ZookeeperDemo {
/**
* 观察者模式
*/
@Test
public void testWatch() throws Exception {
String conn = "s102:2181,s103:2181,s104:2181";
//实例化zk对象
//param1：连接串，指定zk客户端地址；param2：超时时间，超过此时间未获得连接，抛出异常
final ZooKeeper zk = new ZooKeeper(conn, 5000, null);
/**
* 通过回调机制，当监听的节点发生改变，会触发此机制，返回watcher中的方法
* 触发之后，watcher结束
*/
Watcher w = new Watcher() {
public void process(WatchedEvent event) {
System.out.println(event.getPath()+"出事了: "+ event.getType());
try {
//用于监控"/a"节点下数据是否发生变化
zk.getChildren("/a", this, null);
} catch (Exception e) {
e.printStackTrace();
}
}
};
zk.getChildren("/a", w, null);
for ( ; ;){
Thread.sleep(1000);
}
}
}
以上代码执行结果如下：
6>.
