1.1 设置本地仓库，在setting.xml 第53行

  <localRepository>C:\Program Files\Maven\conf\repository</localRepository>

1.2 设置阿里源：

setting.xml，在大概146行

<mirrors>
    <mirror>
      <id>nexus-aliyun</id>
      <mirrorOf>*</mirrorOf>
      <name>Nexus aliyun</name>
      <url>http://maven.aliyun.com/nexus/content/groups/public</url>
    </mirror>
</mirrors>

命令：
mvn help:system : 该命令会打印出所有的Java系统属性和环境变量，首次执行会下载maven-help-plugin，包括pom文件和jar文件。这些文件都被下载到了Maven本地仓库中。

其他：hadoop开发依赖包

 <dependencies>
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-client</artifactId>
            <version>2.8.5</version>
        </dependency>

        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-common</artifactId>
            <version>2.8.5</version>
        </dependency>

        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-hdfs</artifactId>
            <version>2.8.5</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

    </dependencies>