1、在Idea中，建立maven專案，選擇org.apache.maven.archetype:maven-archetype-quickstart，建立一個普通的Java專案（archetypeCatalog:internal），預設會建立 App 類。

2、新增依賴

    <!-- https://mvnrepository.com/artifact/org.apache.hadoop/hadoop-client -->
    <dependency>
      <groupId>org.apache.hadoop</groupId>
      <artifactId>hadoop-client</artifactId>
      <version>2.6.0</version>
    </dependency>
 

 2、新增log4j.properties

#全域性配置
log4j.rootLogger= ERROR,stdout
#Hadoop 日誌配置
log4j.logger.org.apache.hadoop= DEBUG
#控制檯輸出配置
log4j.appender.stdout= org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout= org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern= %5p [%t] - %m%n
 

3、檔案和目錄相關操作

package Hadoop;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;

import java.io.IOException;

/**
 * Hello world!
 *
 */
public class App 
{
    private static Configuration configuration = new Configuration();

    static {
       configuration.set("fs.defaultFS","hdfs://192.168.255.128:9000");
       System.setProperty("HADOOP_USER_NAME","root");
       System.setProperty("hadoop.home.dir","E:/hadoop2.6");
    }

    public static void main( String[] args ) throws IOException {
        //createDir();
        //list();
        //uploadFile();
        //readContent();
        deleteDir();
    }

    /**
     * 建立資料夾
     * @throws IOException
     */
    private static void createDir() throws IOException {
        FileSystem fs = FileSystem.get(configuration);
        fs.mkdirs(new Path("/hdfs2"));
        fs.close();
        System.out.println("建立成功");
    }

    /**
     * 上傳檔案（將檔案拷貝到HDFS上）
     * @throws IOException
     */
    private static void uploadFile() throws IOException {
        FileSystem fs = FileSystem.get(configuration);
        Path srcPath = new Path("E:/1.txt");
        Path targetPath = new Path("/hdfs/");
        fs.copyFromLocalFile(srcPath,targetPath);
        fs.close();
        System.out.println("上傳成功");
    }

    /**
     * 展示hdfs檔案或目錄
     * @throws IOException
     */
    private static void list() throws IOException {
        FileSystem fs = FileSystem.get(configuration);
        FileStatus[] fileStatuses = fs.listStatus(new Path("/"));
        for(FileStatus fileStatus:fileStatuses){
            String type = fileStatus.isDirectory() ? "目錄":"檔案";
            String name = fileStatus.getPath().getName();
            System.out.println(type + "---" + name);
        }
        fs.close();
    }

    /**
     * 讀取檔案內容
     * @throws IOException
     */
    private static void readContent() throws IOException {
        FileSystem fs = FileSystem.get(configuration);
        FSDataInputStream stream = fs.open(new Path("/input/input2.txt"));
        IOUtils.copyBytes(stream,System.out,1024,true);
        IOUtils.closeStream(stream);
        fs.close();
    }

    /**
     * 刪除目錄
     * @throws IOException
     */
    private static void deleteDir() throws IOException {
        FileSystem fs = FileSystem.get(configuration);
        fs.delete(new Path("/hdfs2"),true);
        fs.close();
        System.out.println("刪除成功");
    }
}
 

E:\hadoop2.6\bin下檔案如下