IDEA:2018.2.3
VMware:14
HaDoop:2.7.1
juit:4.12

1. 新建一个Maven项目（不需要选择类型）
   
2. 填写GroupId和 ArtifactId（这个根据大家习惯来写，如果有好的建议欢迎在下面留言）
   
3. 然后选择文件保存路径（个人建议路径里的文件夹名尽量不要有中文）
   
4. 等待项目创建，可以在等待的间隙吧Maven仓库的地址修改一下，毕竟Maven下载包还是挺占地方的

加载好之后我一般都会选择自动引入包

先找到pom.xml文件

然后添加dependency注意，HaDoop的版本号要和虚拟机里的一样

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.hadoop/hadoop-common -->
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-common</artifactId>
            <version>2.7.1</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.hadoop/hadoop-hdfs -->
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-hdfs</artifactId>
            <version>2.7.1</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.hadoop/hadoop-client -->
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-client</artifactId>
            <version>2.7.1</version>
        </dependency>
    </dependencies>

1. bhjb在main/java下新建class
   
2. 这里使用Junit的测试方法，大家可以试一下
   其中的demo是我自己做的一个练习，因为还没有学文件复制所以操作看起来有点费事

 public class HdfsTest {
    //配置链接虚拟机的IP
    public static final String HDFS_PATH = "hdfs://192.168.171.128:9000";
    //hdfs文件系统
    FileSystem fileSystem = null;
    //获取环境对象
    Configuration configuration = null;

    @Before
    public void setUp() throws Exception {
        configuration = new Configuration();
        fileSystem = FileSystem.get(new URI(HDFS_PATH), configuration);
        System.out.println("HDFS APP SETUP");
    }

    @Test
    public void create() throws IOException {
    //创建文件
        FSDataOutputStream outputStream = fileSystem.create(new Path("/hdfsapi/test/a.txt"));
        outputStream.write("hello hadoop".getBytes());
        outputStream.flush();
        outputStream.close();
    }

    @Test
    public void cat() throws IOException {
        FSDataInputStream inputStream = fileSystem.open(new Path("/hdfsapi/test/a.txt"));
        IOUtils.copyBytes(inputStream, System.out, 1024);
        inputStream.close();
    }

    @Test
    public void mkdir() throws IOException {
        fileSystem.mkdirs(new Path("/hdfsapi/test"));
    }

    @Test
    public void upset() throws URISyntaxException, IOException {
    //上传文件,路径大家记得改一下
        String file = "E:/hadoopTest/output/test.txt";
        InputStream inputStream = new FileInputStream(new File(file));
        FSDataOutputStream outputStream = fileSystem.create(new Path("/hdfsapi/park/aaa.txt"));
        IOUtils.copyBytes(inputStream, outputStream, configuration);
//        fileSystem.copyFromLocalFile();底层是调用了IOUtils.copyBytes()
    }

    @Test
    public void download() throws URISyntaxException, IOException {
//        获取输入流
        InputStream in = fileSystem.open(new Path("/park/2.txt"));
//        获取输出流
        String file = "E:/hadoopTest/output/test.txt";
        OutputStream outputStream = new FileOutputStream(new File(file));
        IOUtils.copyBytes(in, outputStream, configuration);
        in.close();
        outputStream.close();
    }

    @Test
    public void demo1() throws URISyntaxException, IOException {
        configuration = new Configuration();
        fileSystem = (FileSystem) FileSystem.get(new URI(HDFS_PATH), configuration);
//        1、在hdfs创建目录teacher。
//        2、在teacher目录下上传文件score.txt。
        String file = "E:/hadoopTest/score.txt";
        InputStream inputStream = new FileInputStream(new File(file));
        OutputStream outputStream = fileSystem.create(new Path("/hdfs/teacher/score.txt"));
        IOUtils.copyBytes(inputStream, outputStream, configuration);
//        3、在hdfs创建目录student，并在student目录下创建新目录Tom、LiMing、Jerry.
        fileSystem.mkdirs(new Path("/hdfs/student/Tom"));
        fileSystem.mkdirs(new Path("/hdfs/student/LiMing"));
        fileSystem.mkdirs(new Path("/hdfs/student/Jerry"));
//        4、在Tom目录下上传information.txt,同时上传到LiMing、Jerry目录下。
        file = "E:/hadoopTest/information.txt";
        inputStream = new FileInputStream(new File(file));
        outputStream = fileSystem.create(new Path("/hdfs/student/Tom/information.txt"));
        IOUtils.copyBytes(inputStream, outputStream, configuration);
//        file = "E:/hadoopTest/information.txt";
        inputStream = new FileInputStream(new File(file));

        outputStream = fileSystem.create(new Path("/hdfs/student/LiMing/information.txt"));
        IOUtils.copyBytes(inputStream, outputStream, configuration);
//        file = "E:/hadoopTest/information.txt";
        inputStream = new FileInputStream(new File(file));

        outputStream = fileSystem.create(new Path("/hdfs/student/Jerry/information.txt"));
        IOUtils.copyBytes(inputStream, outputStream, configuration);
//        5、将student重命名为MyStudent。
        fileSystem.rename(new Path("/hdfs/student"), new Path("/hdfs/MyStudent"));
//        6、将Tom下的information.txt下载到E:/tom目录中
        file = "E:/tom";
        inputStream = fileSystem.open(new Path("/hdfs/MyStudent/Tom/information.txt"));
        outputStream = new FileOutputStream(new File(file));
        IOUtils.copyBytes(inputStream, outputStream, configuration);
//        7、将teacher下的score.txt也下载到此目录
        inputStream = fileSystem.open(new Path("/hdfs/teacher/score.txt"));
        outputStream = new FileOutputStream(new File(file));
        IOUtils.copyBytes(inputStream, outputStream, configuration);
//        8、删除hdfs中的Tom、LiMing目录
        fileSystem.delete(new Path("/hdfs/Tom"), true);
        fileSystem.delete(new Path("/hdfs/LiMing"), true);
        inputStream.close();
        outputStream.close();
    }

    @After
    public void tearDown() throws Exception {
        fileSystem.close();
        configuration = null;
        System.out.println("HDFS APP SHUTDOWN");
    }
}