package p01;import java.io.FileInputStream;import java.io.IOException;import org.apache.commons.io.IOUtils;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.FSDataOutputStream;import org.apache.hadoop.fs.FileSystem;import org.apache.hadoop.fs.Path;public class WriteFile {	public static void main(String[] args) throws IOException {		Configuration conf = new Configuration();		conf.set("fs.defaultFS", "hdfs://192.168.1.110:9000/");		FileSystem fs = FileSystem.get(conf);		// 本地输入流		FileInputStream input = new FileInputStream("e:/a.txt");		// 创建输出流		Path path = new Path("hdfs://192.168.1.110:9000/file.txt");		FSDataOutputStream output = fs.create(path);		// copy		IOUtils.copy(input, output);	}}

HDFSUtil

package p02;import java.net.URI;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.FileSystem;import org.apache.hadoop.fs.LocatedFileStatus;import org.apache.hadoop.fs.Path;import org.apache.hadoop.fs.RemoteIterator;import org.junit.Before;import org.junit.Test;public class HDFSUtil {		FileSystem fs = null;		@Before	public void init() throws Exception {		Configuration conf = new Configuration();		conf.set("fs.defaultFS", "hdfs://192.168.1.110:9000/");		// 以用户名hadoop 访问URI，配置文件是conf		fs = FileSystem.get(new URI("hdfs://192.168.1.110:9000/"), conf, "hadoop");	}		// 文件上传	@Test	public void upload() throws Exception {		fs.copyFromLocalFile(new Path("e:/56e79ea2e1418.jpg"), new Path("hdfs://192.168.1.110:9000/56e79ea2e1418.jpg"));	}		// 文件下载	@Test	public void download() throws Exception {		/*		 * Parameters:			delSrc - whether to delete the src			src - path			dst - path			useRawLocalFileSystem - whether to use RawLocalFileSystem as local file system or not.		 */		fs.copyToLocalFile(false, new Path("hdfs://192.168.1.110:9000/file.txt"), new Path("e:/file2.txt"), true);	}		// 创建文件夹	@Test	public void mkdirs() throws Exception {				fs.mkdirs(new Path("/f1/f2/f3"));	}		// 删除文件或文件夹	@Test	public void rm() throws Exception {		/*		 * Parameters:			f - the path to delete.			recursive - if path is a directory and set to true, the directory is deleted else throws an exception. 			In case of a file the recursive can be set to either true or false.		 */		fs.delete(new Path("/f1"),true);	}		// 文件列表	@Test	public void listFiles() throws Exception {		/*		 * f - is the path		   recursive - if the subdirectories need to be traversed recursively		 */		// listFiles 文件信息，递归遍历		// listStatus 文件、文件夹信息，不提供递归遍历（自行查阅）		RemoteIterator
     
       files = fs.listFiles(new Path("/"), true);		while(files.hasNext()) {			LocatedFileStatus file = files.next();			Path filePath = file.getPath();			String filename = filePath.getName();			System.out.println(filename);		}	}}