代码实例

package oa.epoint.com.hdfs;import java.io.FileOutputStream;import java.io.OutputStream;import java.net.URI;import java.util.Scanner;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.FSDataInputStream;import org.apache.hadoop.fs.FileSystem;import org.apache.hadoop.fs.Path;import org.apache.hadoop.io.IOUtils;public class HdfsTest {    public static void upload() throws Exception {        Configuration conf = new Configuration();        URI uri = new URI("hdfs://100.2.5.1:8020");        FileSystem fs = FileSystem.get(uri, conf, "HDFS");        Path resP = new Path("D://files/file1.txt");        Path destP = new Path("/tmp");        if (!fs.exists(destP)) {            fs.mkdirs(destP);        }        fs.copyFromLocalFile(resP, destP);        fs.close();        System.out.println("***********************");        System.out.println("上传成功！");    }    public static void download() throws Exception {        Configuration conf = new Configuration();        String dest = "hdfs://100.2.5.1/tmp/file1.txt";        String local = "D://files/downloads/file1.txt";        FileSystem fs = FileSystem.get(URI.create(dest), conf, "hdfs");        FSDataInputStream fsdi = fs.open(new Path(dest));        OutputStream output = new FileOutputStream(local);        IOUtils.copyBytes(fsdi, output, 4096, true);        System.out.println("***********************");        System.out.println("下载成功！");    }    public static void main(String[] args) throws Exception {        String arg = "";        Scanner scanner = new Scanner(System.in);        System.out.println("1、上传文件");        System.out.println("2、下载文件");        boolean isconture = true;        while (isconture) {            arg = scanner.next();            if ("1".equals(arg)) {                upload();            } else if ("2".equals(arg)) {                download();            }            System.out.println("是否继续 y/n");            if (scanner.next().equals("n")) {                isconture = false;            }        }        scanner.close();    }}