你好，引入2.6.5的jar版本后，需要引入其依赖的其他jar，上次忘记贴完整了（晕。。。），抱歉！

完整的pom.xml的部分依赖如下：

<!-- dubbo -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>dubbo</artifactId>
    <version>2.6.5</version>
    <exclusions>
        <exclusion>
            <artifactId>curator-framework</artifactId>
            <groupId>org.apache.curator</groupId>
        </exclusion>
        <exclusion>
            <artifactId>curator-client</artifactId>
            <groupId>org.apache.curator</groupId>
        </exclusion>
        <exclusion>
            <artifactId>guava</artifactId>
            <groupId>com.google.guava</groupId>
        </exclusion>
        <exclusion>
            <artifactId>spring-web</artifactId>
            <groupId>org.springframework</groupId>
        </exclusion>
    </exclusions>
</dependency>
<!--下面三个是辅助的依赖jar-->
<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-all</artifactId>
    <version>4.1.32.Final</version>
</dependency>
<dependency>
    <groupId>com.alibaba.spring</groupId>
    <artifactId>spring-context-support</artifactId>
    <version>1.0.2</version>
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5</version>
</dependency>

两个项目：dubboOne跟dubboTwo都要加上哦！我亲测过没问题的！

解决方案：

方案1：可以网上自行下载2.8.4版本的jar，然后手动将其放到你本地的仓库（或者私服）

方案2：将版本号改为2.6.4 或者 2.6.5即可，如下所示：

<!-- dubbo -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>dubbo</artifactId>
    <version>2.6.4</version>
    <exclusions>
        <exclusion>
            <artifactId>curator-framework</artifactId>
            <groupId>org.apache.curator</groupId>
        </exclusion>
        <exclusion>
            <artifactId>curator-client</artifactId>
            <groupId>org.apache.curator</groupId>
        </exclusion>
        <exclusion>
            <artifactId>guava</artifactId>
            <groupId>com.google.guava</groupId>
        </exclusion>
        <exclusion>
            <artifactId>spring-web</artifactId>
            <groupId>org.springframework</groupId>
        </exclusion>
  </exclusions>
</dependency>

不行呀老师。