6、FileStatus類封裝了檔案系統中檔案和目錄的元資料，包括檔案長度、塊大小、備份、修改時間、所有者以及許可權資訊。

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.*;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.io.IOUtils;

import java.io.*;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;

public class HdfsOperate {
    ArrayList<HdfsFile> hdfsfiles;

    public HdfsOperate() {
        this.hdfsfiles = new ArrayList<HdfsFile>();
    }

    /**
     * 獲取hdfs路徑下的檔案列表
     *
     * @param srcpath
     * @return
     */
    public String[] getFileList(String srcpath) {
        try {
            Configuration conf = new Configuration();
            Path path = new Path(srcpath);
            FileSystem fs = path.getFileSystem(conf);
            List<String> files = new ArrayList<String>();
            if (fs.exists(path) && fs.isDirectory(path)) {
                for (FileStatus status : fs.listStatus(path)) {
                    files.add(status.getPath().toString());
                }
            }
            //fs.close();
            return files.toArray(new String[]{});
        } catch (IOException e) {
        } catch (Exception e) {
        }
        return null;
    }

    /**
     * 給定檔名和檔案內容，建立hdfs檔案
     *
     * @param dst
     * @param contents
     * @throws IOException
     */
    public void createFile(String dst, byte[] contents)
            throws IOException {
        Configuration conf = new Configuration();
        Path dstPath = new Path(dst);
        FileSystem fs = dstPath.getFileSystem(conf);

        FSDataOutputStream outputStream = fs.create(dstPath);
        outputStream.write(contents);
        outputStream.close();
        System.out.println("create file " + dst + " success!");
        //fs.close();
    }

    /**
     * 刪除hdfs檔案
     *
     * @param filePath
     * @throws IOException
     */
    public void delete(String filePath) throws IOException {
        Configuration conf = new Configuration();
        Path path = new Path(filePath);
        FileSystem fs = path.getFileSystem(conf);

        boolean isok = fs.deleteOnExit(path);
        if (isok) {
            System.out.println("delete file " + filePath + " success!");
        } else {
            System.out.println("delete file " + filePath + " failure");
        }
        //fs.close();
    }

    /**
     * 建立hdfs目錄
     *
     * @param path
     * @throws IOException
     */
    public void mkdir(String path) throws IOException {
        Configuration conf = new Configuration();
        Path srcPath = new Path(path);
        FileSystem fs = srcPath.getFileSystem(conf);

        boolean isok = fs.mkdirs(srcPath);
        if (isok) {
            System.out.println("create dir ok!");
        } else {
            System.out.println("create dir failure");
        }
        //fs.close();
    }

    /**
     * 讀取hdfs檔案內容，並在控制檯打印出來
     *
     * @param filePath
     * @throws IOException
     */
    public void readFile(String filePath) throws IOException {
        Configuration conf = new Configuration();
        Path srcPath = new Path(filePath);
        FileSystem fs = null;
        URI uri;
        try {
            uri = new URI(filePath);
            fs = FileSystem.get(uri, conf);
        } catch (URISyntaxException e) {
            e.printStackTrace();
        }
        InputStream in = null;
        try {
            in = fs.open(srcPath);
            IOUtils.copyBytes(in, System.out, 4096, false);
        } finally {
            IOUtils.closeStream(in);
        }
    }

    /**
     * 下載hdfs檔案到本地目錄
     *
     * @param dstPath
     * @param srcPath
     * @throws Exception
     */
    public void downloadFile(String dstPath, String srcPath) throws Exception {
        Path path = new Path(srcPath);
        Configuration conf = new Configuration();
        FileSystem hdfs = path.getFileSystem(conf);

        File rootfile = new File(dstPath);
        if (!rootfile.exists()) {
            rootfile.mkdirs();
        }

        if (hdfs.isFile(path)) {
            //只下載非txt檔案
            String fileName = path.getName();
            if (!fileName.toLowerCase().endsWith("txt")) {
                FSDataInputStream in = null;
                FileOutputStream out = null;
                try {
                    in = hdfs.open(path);
                    File srcfile = new File(rootfile, path.getName());
                    if (!srcfile.exists()) srcfile.createNewFile();
                    out = new FileOutputStream(srcfile);
                    IOUtils.copyBytes(in, out, 4096, false);
                } finally {
                    IOUtils.closeStream(in);
                    IOUtils.closeStream(out);
                }
                //下載完後，在hdfs上將原檔案刪除
                this.delete(path.toString());
            }
        } else if (hdfs.isDirectory(path)) {
            File dstDir = new File(dstPath);
            if (!dstDir.exists()) {
                dstDir.mkdirs();
            }
            //在本地目錄上加一層子目錄
            String filePath = path.toString();//目錄
            String subPath[] = filePath.split("/");
            String newdstPath = dstPath + subPath[subPath.length - 1] + "/";
            System.out.println("newdstPath=======" + newdstPath);
            if (hdfs.exists(path) && hdfs.isDirectory(path)) {
                FileStatus[] srcFileStatus = hdfs.listStatus(path);
                if (srcFileStatus != null) {
                    for (FileStatus status : hdfs.listStatus(path)) {
                        //下載子目錄下檔案
                        downloadFile(newdstPath, status.getPath().toString());
                    }
                }
            }
        }
    }

    /**
     * 下載hdfs檔案內容，儲存到記憶體物件中
     *
     * @param srcPath
     * @throws Exception
     */
    public void downloadFileByte(String srcPath) throws Exception {
        Path path = new Path(srcPath);
        FileSystem hdfs = null;
        Configuration conf = new Configuration();
        hdfs = FileSystem.get(URI.create(srcPath), conf);
        if (hdfs.exists(path)) {
            if (hdfs.isFile(path)) {
                //如果是檔案
                FSDataInputStream in = null;
                FileOutputStream out = null;
                try {
                    in = hdfs.open(new Path(srcPath));
                    byte[] t = new byte[in.available()];
                    in.read(t);
                    hdfsfiles.add(new HdfsFile(path.getName(), srcPath, t));
                } finally {
                    IOUtils.closeStream(in);
                    IOUtils.closeStream(out);
                }
            } else {
                //如果是目錄
                FileStatus[] srcFileStatus = hdfs.listStatus(new Path(srcPath));
                for (int i = 0; i < srcFileStatus.length; i++) {
                    String srcFile = srcFileStatus[i].getPath().toString();
                    downloadFileByte(srcFile);
                }
            }
        }
    }

    public ArrayList<HdfsFile> getHdfsfiles() {
        return hdfsfiles;
    }

    /**
     * 將本地目錄或檔案上傳的hdfs
     *
     * @param localSrc
     * @param dst
     * @throws Exception
     */
    public void uploadFile(String localSrc, String dst) throws Exception {

        Configuration conf = new Configuration();
        File srcFile = new File(localSrc);
        if (srcFile.isDirectory()) {
            copyDirectory(localSrc, dst, conf);
        } else {
            copyFile(localSrc, dst, conf);
        }
    }

    /**
     * 拷貝本地檔案hdfs目錄下
     *
     * @param localSrc
     * @param dst
     * @param conf
     * @return
     * @throws Exception
     */
    private boolean copyFile(String localSrc, String dst, Configuration conf) throws Exception {
        File file = new File(localSrc);
        dst = dst + file.getName();
        Path path = new Path(dst);
        FileSystem fs = path.getFileSystem(conf);//FileSystem.get(conf);
        fs.exists(path);
        InputStream in = new BufferedInputStream(new FileInputStream(file));
        OutputStream out = fs.create(new Path(dst));
        IOUtils.copyBytes(in, out, 4096, true);
        in.close();
        return true;
    }

    /**
     * 拷貝本地目錄到hdfs
     * @param src
     * @param dst
     * @param conf
     * @return
     * @throws Exception
     */
    private boolean copyDirectory(String src, String dst, Configuration conf) throws Exception {
        Path path = new Path(dst);
        FileSystem fs = path.getFileSystem(conf);
        if (!fs.exists(path)) {
            fs.mkdirs(path);
        }
        File file = new File(src);

        File[] files = file.listFiles();
        for (int i = 0; i < files.length; i++) {
            File f = files[i];
            if (f.isDirectory()) {
                String fname = f.getName();
                if (dst.endsWith("/")) {
                    copyDirectory(f.getPath(), dst + fname + "/", conf);
                } else {
                    copyDirectory(f.getPath(), dst + "/" + fname + "/", conf);
                }
            } else {
                copyFile(f.getPath(), dst, conf);
            }
        }
        return true;
    }
}