Zookeeper registration center of Dubbo source code

1. Demand

        Use zookeeper as Dubbo's registry

2. Use

     Configure the registry

<dubbo:registry address="zookeeper://127.0.0.1:2181"/>

pom file that needs to be added

<dependency>
    <groupId>org.apache.zookeeper</groupId>
    <artifactId>zookeeper</artifactId>
    <version>3.4.11</version>
</dependency>
<dependency>
    <groupId>com.101tec</groupId>
    <artifactId>zkclient</artifactId>
    <version>0.10</version>
</dependency>