问题1：scala版本跟spark版本不一致

使用maven方式，注意切注意spark与scala有版本对应关系， 详情参考Spark官网相关说明：https://spark.apache.org/docs/latest/index.html
scala版本还要跟工程配置Library添加的Scala版本一致。

问题2：更新依赖等半天没更新完

在pom.xml中添加maven 依赖包时，我就发现不管是否用了翻墙，下载速度都好慢，就1M的东西能下半天，很是苦恼，于是到网上搜资料，然后让我查到了。说是使用阿里的maven镜像就可以了。我于是亲自试了下，速度快的飞起！！！
右键项目选中maven选项，然后选择“open settings.xml”或者 “create settings.xml”，然后把如下代码粘贴进去就可以了。重启IDE，感受速度飞起来的感觉吧！！！
<?xml version=”1.0″ encoding=”UTF-8″?><settings xmlns=”http://maven.apache.org/SETTINGS/1.0.0″ xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xsi:schemaLocation=”http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd”> <mirrors> <!– mirror | Specifies a repository mirror site to use instead of a given repository. The repository that | this mirror serves has an ID that matches the mirrorOf element of this mirror. IDs are used | for inheritance and direct lookup purposes, and must be unique across the set of mirrors. | <mirror> <id>mirrorId</id> <mirrorOf>repositoryId</mirrorOf> <name>Human Readable Name for this Mirror.</name> <url>http://my.repository.com/repo/path</url> </mirror> –>
<mirror> <id>alimaven</id> <name>aliyun maven</name> <url>http://maven.aliyun.com/nexus/content/groups/public/</url> <mirrorOf>central</mirrorOf> </mirror>
<mirror> <id>uk</id> <mirrorOf>central</mirrorOf> <name>Human Readable Name for this Mirror.</name> <url>http://uk.maven.org/maven2/</url> </mirror>
<mirror> <id>CN</id> <name>OSChina Central</name> <url>http://maven.oschina.net/content/groups/public/</url> <mirrorOf>central</mirrorOf> </mirror>
<mirror> <id>nexus</id> <name>internal nexus repository</name> <!– <url>http://192.168.1.100:8081/nexus/content/groups/public/</url>–> <url>http://repo.maven.apache.org/maven2</url> <mirrorOf>central</mirrorOf> </mirror>
</mirrors></settings>