HDFS Java

import java.io.FileNotFoundException;

import java.io.IOException;

importjava.net.URI;

importjava.net.URISyntaxException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.BlockLocation;

import org.apache.hadoop.fs.FileStatus;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.FileUtil;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.hdfs.DistributedFileSystem;

import org.apache.hadoop.hdfs.protocol.DatanodeInfo;

import org.apache.hadoop.hdfs.server.namenode.status_jsp;

public class Test {

    private static Configuration configuration;

    private static FileSystem fileSystem;

    public static FileSystem getFileSystem() throws IOException, URISyntaxException {

        configuration = new Configuration();

        URI uri = new URI("hdfs://Master:9000");

        fileSystem = FileSystem.get(uri, configuration);

        return fileSystem;

    }

    // 创建目录

    public static void mkdir(String creatStringPath) throws IllegalArgumentException, IOException {

        Path creatPath = new Path(creatStringPath);

        fileSystem.mkdirs(creatPath);

        System.out.println("创建成功");

        fileSystem.close();

    }

    // 上传文件至hdfs

    public static void copyToHdfs(String work, String aim) throws IOException {

        Path workPath = new Path(work);

        Path aimPath = new Path(aim);

        fileSystem.copyFromLocalFile(workPath, aimPath);

        fileSystem.close();

    }

    // 从hdfs下载文件

    public static void getFile(String work, String aim) throws IOException {

        Path workPath = new Path(work);

        Path aimPath = new Path(aim);

        fileSystem.copyToLocalFile(workPath, aimPath);

        fileSystem.close();

    }

    // 获取目录下的所有文件

    public static void listAllFile(String aim) throws FileNotFoundException, IOException {

        Path aimPath = new Path(aim);

        FileStatus[] status = fileSystem.listStatus(aimPath);

        Path[] listedPaths = FileUtil.stat2Paths(status);

        for (int i = 0; i < listedPaths.length; i++) {

            System.out.println(listedPaths[i]);

        }

        fileSystem.close();

    }

    // 获取指定文件的位置

    public static void findLocal(String work) throws IOException {

        Path workPath = new Path(work);

        FileStatus fileStatus = fileSystem.getFileStatus(workPath);

        BlockLocation[] blockLocations = fileSystem.getFileBlockLocations(fileStatus, 0, fileStatus.getLen());

        for (int i = 0; i < blockLocations.length; i++) {

            String[] hosts = blockLocations[i].getHosts();

            System.out.println(i + "-" + hosts[0]);

        }

        fileSystem.close();

    }

    // 删除文件操作

    public static void delFile(String work) throws IOException {

        Path workPath = new Path(work);

        fileSystem.delete(workPath, true);

        fileSystem.close();

    }

    // 获取hdfs集群节点信息

    public static void getHDFSNodes() throws IOException {

        DistributedFileSystem distributedFileSystem = (DistributedFileSystem) fileSystem;

        DatanodeInfo[] datanodeInfos = distributedFileSystem.getDataNodeStats();

        for (DatanodeInfo datanodeInfo : datanodeInfos) {

            System.out.println(datanodeInfo.getHostName());

        }

        fileSystem.close();

    }

    public static void main(String[] args) throws IOException, URISyntaxException {

        getFileSystem();

        // 各项功能

        // 1********创建目录r

        // mkdir("/javaAPITest");

        // 2 ********上传文件至hdfs

        // copyToHdfs("/Users/hadoop/Downloads/duet.app", "/javaAPITest");

        // 3********从hdfs下载文件

        // getFile("/javaAPITest/duet.app", "/Users/hadoop/Documents");

        // 4********获取目录下的所有文件

        // listAllFile("/");

        // 5********获取指定文件的位置

        // findLocal("/javaAPITest/duet.app/Contents/Info.plist");

        // 6********删除文件操作

        // delFile("/javaAPITest");

        // 7********获取hdfs集群节点信息

        getHDFSNodes();

    }

}