<dependencies>

        <dependency>

            <groupId>junit</groupId>

            <artifactId>junit</artifactId>

            <version>4.10</version>

        </dependency>

        <!-- hadoop Client -->

        <dependency>

            <groupId>org.apache.hadoop</groupId>

            <artifactId>hadoop-client</artifactId>

            <version>${hadoop.version}</version>

        </dependency>

</dependencies>

package com.zuoyan.hadoop.hdfs;

import java.io.File;

import java.io.FileInputStream;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.FSDataInputStream;

import org.apache.hadoop.fs.FSDataOutputStream;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.io.IOUtils;

/**

 * use java api operate hdfs

 *

 * @author beifeng

 *

 */

public class HdfsApp {

    // get FileSystem

    public static FileSystem getFileSystem() throws Exception {

        Configuration conf = new Configuration();

        FileSystem fileSystem = FileSystem.get(conf);

        return fileSystem;

    }

    public static void read(String fileName) throws Exception {

        FileSystem fileSystem = getFileSystem();

        // read Path

        Path readPath = new Path(fileName);

        FSDataInputStream inStream = fileSystem.open(readPath);

        try {

            IOUtils.copyBytes(inStream, System.out, 4096, false);

        } catch (Exception e) {

            // TODO: handle exception

            e.printStackTrace();

        } finally {

            // if Exception close Stream

            IOUtils.closeStream(inStream);

        }

    }

    public static void main(String[] args) throws Exception{

            //String fileName = "/user/beifeng/mapreduce/wordcount/input/wc.input";

            //read(fileName);

            FileSystem fileSystem = getFileSystem();

            //write path

            String putFileName = "/user/beifeng/put-wc.input";

            Path writePath = new Path(putFileName);

            FSDataOutputStream outputStream = fileSystem.create(writePath);

            FileInputStream inputStream = new FileInputStream(

                    new File("/opt/modules/hadoop-2.5.0/wc.input"));

            try {

                IOUtils.copyBytes(inputStream, outputStream, 4096,false);

            } catch (Exception e) {

                // TODO: handle exception

                inputStream.close();

                outputStream.close();

            }

    }

}