编写Java代码对HDFS进行增删改查操作代码实例

import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.net.URI;import org.apache.commons.compress.utils.IOUtils;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.BlockLocation;import org.apache.hadoop.fs.FSDataInputStream;import org.apache.hadoop.fs.FSDataOutputStream;import org.apache.hadoop.fs.FileStatus;import org.apache.hadoop.fs.FileSystem;import org.apache.hadoop.fs.Path;public class FileOpreation {	public static void main(String[] args) throws IOException {		//CreateFile();		//DeleteFile();		//CopyFileToHDFS();		//MkDirs();		//DelDirs();		ListDirectory();		DownLoad();	}	public static void CreateFile() throws IOException {		String uri = "hdfs://Alvis:9000";		Configuration configuration =new Configuration();		FileSystem fSystem = FileSystem.get(URI.create(uri), configuration);		byte[] file_content_buff="hello hadoop world, test write file !/n".getBytes();		Path dfs = new Path("/home/test.txt");		FSDataOutputStream outputStream = fSystem.create(dfs);		outputStream.write(file_content_buff.length);	}	public FileOpreation() {		// TODO Auto-generated constructor stub	}public static void DeleteFile() throws IOException {		String uri = "hdfs://Alvis:9000";		Configuration configuration =new Configuration();		FileSystem fSystem = FileSystem.get(URI.create(uri), configuration);		Path deletf = new Path("/home/test.txt");		boolean delResult = fSystem.delete(deletf,true);		System.out.println(delResult==true?"删除成功":"删除失败");	}  	public static void CopyFileToHDFS() throws IOException {		String uri = "hdfs://Alvis:9000";		Configuration configuration =new Configuration();		FileSystem fSystem = FileSystem.get(URI.create(uri), configuration);		Path src = new Path("E://SerializationTest//APITest.txt");		Path dest_src = new Path("/home");		fSystem.copyFromLocalFile(src, dest_src);	}		public static void MkDirs() throws IOException {		String uri = "hdfs://Alvis:9000";		Configuration configuration =new Configuration();		FileSystem fSystem = FileSystem.get(URI.create(uri), configuration);		Path src = new Path("/Test");		fSystem.mkdirs(src);			}		public static void DelDirs() throws IOException {		String uri = "hdfs://Alvis:9000";		Configuration configuration = new Configuration();		FileSystem fSystem = FileSystem.get(URI.create(uri), configuration);		Path src = new Path("/Test");		fSystem.delete(src);	}		public static void ListDirectory() throws IOException {		String uri = "hdfs://Alvis:9000";		Configuration configuration = new Configuration();		FileSystem fSystem = FileSystem.get(URI.create(uri), configuration);		FileStatus[] fStatus = fSystem.listStatus(new Path("/output"));		for(FileStatus status : fStatus)			if (status.isFile()) {				System.out.println("文件路径："+status.getPath().toString());				System.out.println("文件路径 getReplication："+status.getReplication());				System.out.println("文件路径 getBlockSize:"+status.getBlockSize());				BlockLocation[] blockLocations = fSystem.getFileBlockLocations(status, 0, status.getBlockSize());				for(BlockLocation location : blockLocations){					System.out.println("主机名："+location.getHosts()[0]);					System.out.println("主机名："+location.getNames()[0]);			  }		  }			else {				System.out.println("directory:"+status.getPath().toString());			}	}		public static void DownLoad() throws IOException {		Configuration configuration = new Configuration();		configuration.set("fs.defaultFS", "hdfs://Alvis:9000");		FileSystem fSystem =FileSystem.get(configuration);		FSDataInputStream inputStream =fSystem.open( new Path("/input/wc.jar"));		FileOutputStream outputStream = new FileOutputStream(new File("E://LearnLife//DownLoad//wc.jar"));		IOUtils.copy(inputStream, outputStream);		System.out.println("下载成功！");	}}