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    cmd用来在windows上跑。。
    sh用来在linux上跑,以后听到linux的shell脚本，.sh就是
    aa.png
    aa.png

    1. package com.moon.utils;
    3. import java.io.FileOutputStream;
    4. import java.io.InputStream;
    5. import org.apache.hadoop.conf.Configuration;
    6. import org.apache.hadoop.fs.FSDataInputStream;
    7. import org.apache.hadoop.fs.FSDataOutputStream;
    8. import org.apache.hadoop.fs.FileStatus;
    9. import org.apache.hadoop.fs.FileSystem;
    10. import org.apache.hadoop.fs.Path;
    12. public class HdfsUtils {
    13.     private static Configuration conf;
    14.     static {
    15.         conf = new Configuration();
    16.         conf.set("fs.defaultFS", "hdfs://127.0.0.1:9000");
    17.     }
    19.     // 查看文件列表
    20.     public static void ls(String path) {
    21.         try {
    22.             FileSystem fs = FileSystem.get(conf);
    23.             FileStatus[] arr = fs.listStatus(new Path(path));
    24.             for (FileStatus f : arr) {
    25.                 System.out.println(f.getPath().getName());
    26.             }
    27.             fs.close();
    28.         } catch (Exception e) {
    29.             e.printStackTrace();
    30.         }
    31.     }
    33.     // 创建目录
    34.     public static void mkdir(String path) {
    35.         try {
    36.             FileSystem fs = FileSystem.get(conf);
    37.             fs.mkdirs(new Path(path));
    38.             System.out.println("创建目录成功");
    39.             fs.close();
    40.         } catch (Exception e) {
    41.             e.printStackTrace();
    42.         }
    43.     }
    45.     // 删除
    46.     public static void delete(String path) {
    47.         try {
    48.             FileSystem fs = FileSystem.get(conf);
    49.             fs.delete(new Path(path));
    50.             System.out.println("删除成功");
    51.             fs.close();
    52.         } catch (Exception e) {
    53.             e.printStackTrace();
    54.         }
    55.     }
    57.     // ntfs->hdfs 要求传本地路径和云端路径。在真实开发中是不适合的
    58.     public static void uploadToHdfs(String localPath, String hdfsPath) {
    59.         try {
    60.             FileSystem fs = FileSystem.get(conf);
    61.             fs.copyFromLocalFile(new Path(localPath), new Path(hdfsPath));
    62.             System.out.println("上传成功");
    63.             fs.close();
    64.         } catch (Exception e) {
    65.             e.printStackTrace();
    66.         }
    67.     }
    69.     // ntfs->hdfs uploadToHdfs改良版
    70.     public static void uploadToHdfs(InputStream inputStream, String hdfsPath) {
    71.         try {
    72.             FileSystem fs = FileSystem.get(conf);
    73.             FSDataOutputStream outputStream = fs.create(new Path(hdfsPath));
    74.             byte[] buf = new byte[1024];
    75.             int len;
    76.             while ((len = inputStream.read(buf)) != -1) {
    77.                 outputStream.write(buf, 0, len);
    78.                 outputStream.flush();
    79.             }
    80.             System.out.println("上传成功");
    81.             outputStream.close();
    82.             inputStream.close();
    83.             fs.close();
    84.         } catch (Exception e) {
    85.             e.printStackTrace();
    86.         }
    87.     }
    89.     // hdfs->ntfs
    90.     public static void downloadTolocal(String hdfsPath, String localPath) {
    91.         try {
    92.             FileSystem fs = FileSystem.get(conf);
    93.             FSDataInputStream dataInputStream = fs.open(new Path(hdfsPath));
    94.             FileOutputStream outputStream = new FileOutputStream(localPath);
    95.             byte[] buf = new byte[1024];
    96.             int len;
    97.             while ((len = dataInputStream.read(buf)) != -1) {
    98.                 outputStream.write(buf, 0, len);
    99.                 outputStream.flush();
    100.             }
    101.             System.out.println("下载成功");
    102.             outputStream.close();
    103.             dataInputStream.close();
    104.             fs.close();
    105.         } catch (Exception e) {
    106.             e.printStackTrace();
    107.         }
    108.     }
    110.     // 测试主函数
    111.     public static void main(String[] args) {
    112.         //
    113.     }
    114. }

    你们课下假如有人去做做这个试验，那么我中午发的压缩包，记得解压一定要在C:/hadoop路径。然后记得配个环境变量，然后格式化，打开服务。