代码下载地址：

一：环境介绍

hadoop：2.6

Ubuntu：15.10

eclipse：3.8.1

二：操作包含

推断某个目录是否存在              isExist(folder);

创建目录                                    mkdir(folder);

删除目录                                    rmr(folder);

列出全部目录                 ls(folder);

递归列出全部目录                      lsr(folder);

上传文件                                        put(local, folder);

下载文件                                        get(folder,local1);

删除文件                                        rm(folder);

显示文件                                        cat(folder);

三：代码演示

package user_thing_tuijian;import java.io.IOException;import java.net.URI;import java.net.URISyntaxException;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.FSDataInputStream;import org.apache.hadoop.fs.FileStatus;import org.apache.hadoop.fs.FileSystem;import org.apache.hadoop.fs.Path;import org.apache.hadoop.io.IOUtils;public class hdfsGYT {		private static  final String HDFS = "hdfs://127.0.0.1:9000/";	public hdfsGYT(String hdfs,  Configuration conf ){		this.hdfsPath = hdfs;		this.conf = conf;	}	public hdfsGYT() {		// TODO Auto-generated constructor stub	}	private String hdfsPath;	private Configuration conf = new Configuration() ;		public static void main(String[] args) throws IOException, URISyntaxException{		hdfsGYT hdfsgyt = new hdfsGYT();		String folder = HDFS + "mr/groom_system/small2.csv";		String local = "/home/thinkgamer/Java/hadoop_shizhan/src/user_thing_tuijian/small2.csv";		String local1 = "/home/thinkgamer/Java/hadoop_shizhan/src/user_thing_tuijian";		//推断某个目录是否存在		//hdfsgyt.isExist(folder);		//创建目录		//hdfsgyt.mkdir(folder);		//删除目录		//hdfsgyt.rmr(folder);		//列出全部目录		//hdfsgyt.ls(folder);		//递归列出全部目录		//hdfsgyt.lsr(folder);		//上传文件		//hdfsgyt.put(local, folder);		//下载文件		//hdfsgyt.get(folder,local1);		//删除文件		//hdfsgyt.rm(folder);		//显示文件		//hdfsgyt.cat(folder);	}	//显示文件	private void cat(String folder) throws IOException, URISyntaxException {		// 与hdfs建立联系		FileSystem fs = FileSystem.get(new URI(HDFS),new Configuration());		Path path = new Path(folder);		 FSDataInputStream fsdis = null;	        System.out.println("cat: " + folder);	        try {  	            fsdis =fs.open(path);	            IOUtils.copyBytes(fsdis, System.out, 4096, false);  	          } finally {  	            IOUtils.closeStream(fsdis);	            fs.close();	          }	}	//删除文件	private void rm(String folder) throws IOException, URISyntaxException {		//与hdfs建立联系		FileSystem fs = FileSystem.get(new URI(HDFS),new Configuration());		Path path = new Path(folder);		if(fs.deleteOnExit(path)){			fs.delete(path);			System.out.println("delete:" + folder);		}else{			System.out.println("The fiel is not exist!");		}		fs.close();	}		//下载文件	private void get(String remote,  String local) throws IllegalArgumentException, IOException, URISyntaxException {		// 建立联系		FileSystem fs = FileSystem.get(new URI(HDFS), new Configuration());		fs.copyToLocalFile(new Path(remote), new Path(local));		System.out.println("Get From :   " + remote  + "   To :" + local);		fs.close();	}		//上传文件	private void put(String local, String remote) throws IOException, URISyntaxException {		// 建立联系		FileSystem fs = FileSystem.get(new URI(HDFS), new Configuration());		fs.copyFromLocalFile(new Path(local), new Path(remote));		System.out.println("Put :" + local  + "   To : " + remote);		fs.close();	}	//递归列出全部目录	private void lsr(String folder) throws IOException, URISyntaxException {		//与hdfs建立联系		FileSystem fs = FileSystem.get(new URI(HDFS),new Configuration());		Path path = new Path(folder);		//得到该目录下的全部文件		FileStatus[] fileList = fs.listStatus(path);		for (FileStatus f : fileList) {            System.out.printf("name: %s   |   folder: %s  |   size: %d\n", f.getPath(),  f.isDir() , f.getLen());            try{            	FileStatus[] fileListR = fs.listStatus(f.getPath());            	for(FileStatus fr:fileListR){                    System.out.printf("name: %s   |   folder: %s  |   size: %d\n", fr.getPath(),  fr.isDir() , fr.getLen());            	}            }finally{            	continue;            }        }		fs.close();	}		//列出全部目录	private void ls(String folder) throws IOException, URISyntaxException {		//与hdfs建立联系		FileSystem fs = FileSystem.get(new URI(HDFS),new Configuration());		Path path = new Path(folder);		//得到该目录下的全部文件		FileStatus[] fileList = fs.listStatus(path);		for (FileStatus f : fileList) {            System.out.printf("name: %s   |   folder: %s  |   size: %d\n", f.getPath(),  f.isDir() , f.getLen());        }		fs.close();	}	//删除目录	private void rmr(String folder) throws IOException, URISyntaxException {		//与hdfs建立联系		FileSystem fs = FileSystem.get(new URI(HDFS),new Configuration());		Path path = new Path(folder);		fs.delete(path);		System.out.println("delete:" + folder);		fs.close();	}		//创建目录	public void mkdir(String folder) throws IOException, URISyntaxException {		//与hdfs建立联系		FileSystem fs = FileSystem.get(new URI(HDFS),new Configuration());		Path path = new Path(folder);		if (!fs.exists(path)) {			fs.mkdirs(path);			System.out.println("Create: " + folder);		}else{			System.out.println("it is have exist:" + folder);		}		fs.close();		}		//推断某个目录是否存在	private void isExist(String folder) throws IOException, URISyntaxException {		//与hdfs建立联系		FileSystem fs = FileSystem.get(new URI(HDFS),new Configuration());		Path path = new Path(folder);		if(fs.exists(path)){			System.out.println("it is have exist:" + folder);		}else{			System.out.println("it is not exist:" + folder);		}			fs.close();	}	}