一、基本概念：
1）Dubbo是管理中间层的工具,在业务层到数据仓库间有非常多服务的接入和服务提供者需要调度，
dubbo提供一个框架解决这个问题。这个框架要完成调度必须要有一个分布式的注册中心,
存储所有服务的元数据,用到zookeeper。
2）zookeeper用来注册服务和负载均衡。
二、dubbo和zookeeper的使用：
1、引入相关依赖
下面的放在父工程下：
<!-- 集中定义依赖版本号 -->
<properties>
<junit.version>4.12</junit.version>
<spring.version>5.0.5.RELEASE</spring.version>
<pagehelper.version>4.1.4</pagehelper.version>
<servlet-api.version>2.5</servlet-api.version>
<dubbo.version>2.6.0</dubbo.version>
<zookeeper.version>3.4.7</zookeeper.version>
<zkclient.version>0.1</zkclient.version>
<mybatis.version>3.4.5</mybatis.version>
<mybatis.spring.version>1.3.1</mybatis.spring.version>
<mybatis.paginator.version>1.2.15</mybatis.paginator.version>
<mysql.version>5.1.32</mysql.version>
<druid.version>1.0.9</druid.version>
<commons-fileupload.version>1.3.1</commons-fileupload.version>
<spring.security.version>5.0.5.RELEASE</spring.security.version>
</properties>
<!-- dubbo和Zookeeper相关 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dubbo</artifactId>
<version>${dubbo.version}</version>
</dependency>
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>${zookeeper.version}</version>
</dependency>
<dependency>
<groupId>com.github.sgroschupf</groupId>
<artifactId>zkclient</artifactId>
<version>${zkclient.version}</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.47</version>
</dependency>
<dependency>
<groupId>javassist</groupId>
<artifactId>javassist</artifactId>
<version>3.12.1.GA</version>
</dependency>
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
<version>1.10</version>
</dependency>
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper</artifactId>
<version>${pagehelper.version}</version>
</dependency>
下面的放在公共模块下：
<!-- dubbo相关 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dubbo</artifactId>
</dependency>
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
</dependency>
<dependency>
<groupId>com.github.sgroschupf</groupId>
<artifactId>zkclient</artifactId>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
</dependency>
<dependency>
<groupId>javassist</groupId>
<artifactId>javassist</artifactId>
</dependency>
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
</dependency>
2、在公共模块的resources添加zk.properties配置文件。
zk.address=localhost:2181
3、在服务公共模块的resources添加服务公共模块applicationContext-dubbo.xml配置文件。
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:dubbo="http://code.alibabatech.com/schema/dubbo" xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<!--指定暴露服务的端口，如果不指定默认为20880-->
<dubbo:protocol name="dubbo" port="${dubbo.port}"/>
<dubbo:application name="${dubbo.application}" />
<dubbo:registry protocol="zookeeper" address="${zk.address}" />
<dubbo:annotation package="com.qingcheng.service" />
<!--<context:annotation-config/>-->
</beans>
4、在web公共模块的resources添加web公共模块的applicationContext-dubbo.xml配置文件。
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<!-- 引用dubbo 服务 -->
<dubbo:application name="${dubbo.application}" />
<dubbo:registry protocol="zookeeper" address="${zk.address}"/>
<dubbo:annotation package="com.qingcheng.controller" />
</beans>
5、在服务子模块的resources添加服务子模块dubbo.properties配置文件。
dubbo.port=20881
dubbo.application=goods
6、在web子模块的resources添加web子模块的dubbo.properties配置文件。
dubbo.application=manager
7、解压zookeeper安包，在conf下添加zoo.cfg配置文件，要使用时，在bin下双击启动zkServer.cmd
zoo.cfg配置文件:
# The number of milliseconds of each tick
tickTime=2000
# The number of ticks that the initial
# synchronization phase can take
initLimit=10
# The number of ticks that can pass between
# sending a request and getting an acknowledgement
syncLimit=5
# the directory where the snapshot is stored.
# do not use /tmp for storage, /tmp here is just
# example sakes.
dataDir=/tmp/zookeeper
# the port at which the clients will connect
clientPort=2181
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# Be sure to read the maintenance section of the
# administrator guide before turning on autopurge.
#
# http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
#
# The number of snapshots to retain in dataDir
#autopurge.snapRetainCount=3
# Purge task interval in hours
# Set to "0" to disable auto purge feature
#autopurge.purgeInterval=1
zookeeper安装包如果有需要可以私聊！！！