需要注意以下几点

1.所以的包都是org.apache.hadoop.XXX

2.三个配置文件要放到指定文件夹中等待文件系统读取（src/main/resources）:core-site.xml hdfs-site.xml log4j.properties

3.文件路径指向要正确

package com.cenzhongman.hadoop.hdfs;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;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;public class HdfsApp {    /**     * to get fileSystem     *      * @return fileSystem     */    public static FileSystem getFileSystem() {        // 1.read configuration information : core-site.xml core-default.xml        // hdfs-site.xml hdfs-default.xml        Configuration conf = new Configuration();        // 2.get fileSystem        org.apache.hadoop.fs.FileSystem fileSystem = null;        try {            fileSystem = org.apache.hadoop.fs.FileSystem.get(conf);        } catch (IOException e) {            e.printStackTrace();        }        // 3.return fileSystem        return fileSystem;    }    /**     * read data form fileSystem     *      * @param fileName     */    public static void read(String fileName) {        // 1.get fileSystem        FileSystem fileSystem = getFileSystem();        System.out.println(fileSystem);        // 2.read path        Path readPath = new Path(fileName);        // 3.open file and get FSDataInputStream        FSDataInputStream inStream = null;        try {            inStream = fileSystem.open(readPath);        } catch (IOException e1) {            e1.printStackTrace();        }        // 4.read file info        try {            // read            IOUtils.copyBytes(inStream, System.out, 4096, false);        } catch (Exception e) {            e.printStackTrace();        } finally {            // close stream            IOUtils.closeStream(inStream);        }    }    public static void uploadFile(String fromFilePath, String putFilePath) {        // 1.get fileSystem        FileSystem fileSystem = getFileSystem();        // 2.write path        Path weitePath = new Path(putFilePath);        // 3.Output Stream        FSDataOutputStream ourStream = null;        try {            ourStream = fileSystem.create(weitePath);        } catch (IOException e1) {            e1.printStackTrace();        }        // 4.input Stream        FileInputStream inStream = null;        try {            inStream = new FileInputStream(new File(fromFilePath));        } catch (FileNotFoundException e1) {            // TODO Auto-generated catch block            e1.printStackTrace();        }        // 5.stream read/write        try {            // read            IOUtils.copyBytes(inStream, ourStream, 4096, false);        } catch (Exception e) {            e.printStackTrace();        } finally {            // close stream            IOUtils.closeStream(inStream);            IOUtils.closeStream(ourStream);        }    }    public static void main(String[] args) throws Exception {        String fileName = "/tmp/hadoop-yarn/staging/history/done_intermediate/cen/job_1497948413653_0001_conf.xml";        read(fileName);        String putFilePath = "/user/cen/output/file-output-test.xml";        String fromFilePath = "/usr/local/hadoop-2.5.0/input/core-site.xml";        uploadFile(fromFilePath, putFilePath);    }}