dubbo客户端版本选择

dubbo 2.5.x 及 2.5.x以前的版本，用zkclient操作zookeeper

pom.xml配置：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>dubbo</artifactId>
    <version>2.5.6</version>
</dependency>
<!-- zkclient -->
<dependency>
    <groupId>com.101tec</groupId>
    <artifactId>zkclient</artifactId>
    <version>0.10</version>
</dependency>

applicationContext.xml文件头配置：（注意命名空间）

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd 
    http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">

dubbo 2.6.x及以后的版本，用curator操作zookeeper

pom.xml配置：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>dubbo</artifactId>
    <version>2.6.2</version>
</dependency>
<!-- curator -->
<dependency>
    <groupId>org.apache.curator</groupId>
    <artifactId>curator-framework</artifactId>
    <version>2.12.0</version>
</dependency>

applicationContext.xml文件头配置：（注意命名空间）

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd 
    http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd">

注：2.6.x以后集成spring，命名空间也要修改，否则会有如下异常：

Configuration problem: Unable to locate Spring NamespaceHandler for XML schema namespace [http://dubbo.apache.org/schema/dubbo]