HDFS文件目录操作代码

分布式文件系统HDFS中对文件/目录的相关操作代码，整理了一下，大概包括以下部分：

• 文件夹的新建、删除、重命名
• 文件夹中子文件和目录的统计
• 文件的新建及显示文件内容
• 文件在local和remote间的相互复制
• 定位文件在HDFS中的位置，以及副本存放的主机
• HDFS资源使用情况

1. 新建文件夹

public void mkdirs(String folder) throws IOException {
    Path path = new Path(folder);
    FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
    if (!fs.exists(path)) {
        fs.mkdirs(path);
        System.out.println("Create: " + folder);
    }
    fs.close();
}

2. 删除文件夹

public void rmr(String folder) throws IOException {
    Path path = new Path(folder);
    FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
    fs.deleteOnExit(path);
    System.out.println("Delete: " + folder);
    fs.close();
}

3. 文件重命名

public void rename(String src, String dst) throws IOException {
    Path name1 = new Path(src);
    Path name2 = new Path(dst);
    FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
    fs.rename(name1, name2);
    System.out.println("Rename: from " + src + " to " + dst);
    fs.close();
}

4. 列出文件夹中的子文件及目录

public void ls(String folder) throws IOException {
    Path path = new Path(folder);
    FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
    FileStatus[] list = fs.listStatus(path);

    System.out.println("ls: " + folder);
    System.out.println("==========================================================");
    for (FileStatus f : list) {
        System.out.printf("name: %s, folder: %s, size: %d\n", f.getPath(), f.isDirectory(), f.getLen());
    }
    System.out.println("==========================================================");
    fs.close();
}

5. 创建文件，并添加内容

public void createFile(String file, String content) throws IOException {
    FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
    byte[] buff = content.getBytes();
    FSDataOutputStream os = null;
    try {
        os = fs.create(new Path(file));
        os.write(buff, 0, buff.length);
        System.out.println("Create: " + file);
    } finally {
        if (os != null)
            os.close();
    }
    fs.close();
}

6. 将local数据复制到remote

public void copyFile(String local, String remote) throws IOException {
    FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
    fs.copyFromLocalFile(new Path(local), new Path(remote));
    System.out.println("copy from: " + local + " to " + remote);
    fs.close();
}

7. 将remote数据下载到local

public void download(String remote, String local) throws IOException {
    Path path = new Path(remote);
    FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
    fs.copyToLocalFile(path, new Path(local));
    System.out.println("download: from" + remote + " to " + local);
    fs.close();
}

8. 显示文件内容

    public String cat(String remoteFile) throws IOException {
        Path path = new Path(remoteFile);
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        FSDataInputStream fsdis = null;
        System.out.println("cat: " + remoteFile);

        OutputStream baos = new ByteArrayOutputStream();
        String str = null;

        try {
            fsdis = fs.open(path);
            IOUtils.copyBytes(fsdis, baos, 4096, false);
            str = baos.toString();
        } finally {
            IOUtils.closeStream(fsdis);
            fs.close();
        }
        System.out.println(str);
        return str;
    }

9. 定位一个文件在HDFS中存储的位置，以及多个副本存储在集群哪些节点上

public void location() throws IOException {
    String folder = hdfsPath + "create/";
    String file = "t2.txt";
    FileSystem fs = FileSystem.get(URI.create(hdfsPath), new Configuration());
    FileStatus f = fs.getFileStatus(new Path(folder + file));
    BlockLocation[] list = fs.getFileBlockLocations(f, 0, f.getLen());

    System.out.println("File Location: " + folder + file);
    for (BlockLocation bl : list) {
        String[] hosts = bl.getHosts();
        for (String host : hosts) {
            System.out.println("host:" + host);
        }
    }
    fs.close();
}

10. 获取HDFS集群存储资源使用情况

public void getTotalCapacity() {
    try {
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        FsStatus fsStatus = fs.getStatus();
        System.out.println("总容量:" + fsStatus.getCapacity());
        System.out.println("使用容量:" + fsStatus.getUsed());
        System.out.println("剩余容量:" + fsStatus.getRemaining());
    } catch (IOException e) {
        e.printStackTrace();
    }
}

完整代码

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URI;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.ContentSummary;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.FsStatus;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.mapred.JobConf;

/*
* HDFS工具类
*
*/
public class Hdfs {

    private static final String HDFS = "hdfs://10.20.14.47:8020/";

    public Hdfs(Configuration conf) {
        this(HDFS, conf);
    }

    public Hdfs(String hdfs, Configuration conf) {
        this.hdfsPath = hdfs;
        this.conf = conf;
    }

    private String hdfsPath;
    private Configuration conf;

    public static void main(String[] args) throws IOException {
        JobConf conf = config();
        Hdfs hdfs = new Hdfs(conf);
        hdfs.createFile("/create/t2.txt", "12");
        hdfs.location();
    }

    public static JobConf config() {
        JobConf conf = new JobConf(Hdfs.class);
        conf.setJobName("HdfsDAO");
        conf.addResource("classpath:/hadoop/core-site.xml");
        conf.addResource("classpath:/hadoop/hdfs-site.xml");
        conf.addResource("classpath:/hadoop/mapred-site.xml");
        return conf;
    }

    /*
     * 创建文件夹
     */
    public void mkdirs(String folder) throws IOException {
        Path path = new Path(folder);
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        if (!fs.exists(path)) {
            fs.mkdirs(path);
            System.out.println("Create: " + folder);
        }
        fs.close();
    }

    /*
     * 删除文件夹
     */
    public void rmr(String folder) throws IOException {
        Path path = new Path(folder);
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        fs.deleteOnExit(path);
        System.out.println("Delete: " + folder);
        fs.close();
    }

    /*
     * 文件重命名
     */
    public void rename(String src, String dst) throws IOException {
        Path name1 = new Path(src);
        Path name2 = new Path(dst);
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        fs.rename(name1, name2);
        System.out.println("Rename: from " + src + " to " + dst);
        fs.close();
    }

    /*
     * 列出文件夹中的子文件及目录
     */
    public void ls(String folder) throws IOException {
        Path path = new Path(folder);
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        FileStatus[] list = fs.listStatus(path);

        System.out.println("ls: " + folder);
        System.out.println("==========================================================");
        for (FileStatus f : list) {
            System.out.printf("name: %s, folder: %s, size: %d\n", f.getPath(), f.isDirectory(), f.getLen());
        }
        System.out.println("==========================================================");
        fs.close();
    }

    /*
     * 创建文件，并添加内容
     */
    public void createFile(String file, String content) throws IOException {
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        byte[] buff = content.getBytes();
        FSDataOutputStream os = null;
        try {
            os = fs.create(new Path(file));
            os.write(buff, 0, buff.length);
            System.out.println("Create: " + file);
        } finally {
            if (os != null)
                os.close();
        }
        fs.close();
    }

    /*
     * 将local的数据复制到remote
     */
    public void copyFile(String local, String remote) throws IOException {
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        fs.copyFromLocalFile(new Path(local), new Path(remote));
        System.out.println("copy from: " + local + " to " + remote);
        fs.close();
    }

    /*
     * 将remote数据下载到local
     */
    public void download(String remote, String local) throws IOException {
        Path path = new Path(remote);
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        fs.copyToLocalFile(path, new Path(local));
        System.out.println("download: from" + remote + " to " + local);
        fs.close();
    }

    /*
     * 显示文件内容
     */
    public String cat(String remoteFile) throws IOException {
        Path path = new Path(remoteFile);
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
        FSDataInputStream fsdis = null;
        System.out.println("cat: " + remoteFile);

        OutputStream baos = new ByteArrayOutputStream();
        String str = null;

        try {
            fsdis = fs.open(path);
            IOUtils.copyBytes(fsdis, baos, 4096, false);
            str = baos.toString();
        } finally {
            IOUtils.closeStream(fsdis);
            fs.close();
        }
        System.out.println(str);
        return str;
    }

    /*
     * 定位一个文件在HDFS中存储的位置，以及多个副本存储在集群哪些节点上
     */
    public void location() throws IOException {
        String folder = hdfsPath + "create/";
        String file = "t2.txt";
        FileSystem fs = FileSystem.get(URI.create(hdfsPath), new Configuration());
        FileStatus f = fs.getFileStatus(new Path(folder + file));
        BlockLocation[] list = fs.getFileBlockLocations(f, 0, f.getLen());

        System.out.println("File Location: " + folder + file);
        for (BlockLocation bl : list) {
            String[] hosts = bl.getHosts();
            for (String host : hosts) {
                System.out.println("host:" + host);
            }
        }
        fs.close();
    }

    /*
     * 获取HDFS资源使用情况
     */
    public void getTotalCapacity() {
        try {
            FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
            FsStatus fsStatus = fs.getStatus();
            System.out.println("总容量:" + fsStatus.getCapacity());
            System.out.println("使用容量:" + fsStatus.getUsed());
            System.out.println("剩余容量:" + fsStatus.getRemaining());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /*
     * 获取某文件中包含的目录数，文件数，及占用空间大小
     */
    public void getContentSummary(String path) {
        ContentSummary cs = null;
        try {
            FileSystem fs = FileSystem.get(URI.create(hdfsPath), conf);
            cs = fs.getContentSummary(new Path(path));
        } catch (Exception e) {
            e.printStackTrace();
        }

        // 目录数
        Long directoryCount = cs.getDirectoryCount();
        // 文件数
        Long fileCount = cs.getFileCount();
        // 占用空间
        Long length = cs.getLength();

        System.out.println("目录数:" + directoryCount);
        System.out.println("文件数:" + fileCount);
        System.out.println("占用空间:" + length);
    }
}