1、创建目录

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.Path;

public class MakeDir {

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

		Configuration conf = new Configuration();

		FileSystem fs = FileSystem.get(conf);

		Path path = new Path("/user/hadoop/data/20130709");

		fs.create(path);

		fs.close();

	}

}

2、删除目录

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.Path;

public class DeleteDir {

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

		Configuration conf = new Configuration();

		FileSystem fs = FileSystem.get(conf);

		Path path = new Path("/user/hadoop/data/20130710");

		fs.delete(path);

		fs.close();

	}

}

3、写文件

import java.io.IOException;

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();

		FileSystem fs = FileSystem.get(conf);

		Path path = new Path("/user/hadoop/data/write.txt");

		FSDataOutputStream out = fs.create(path);

		out.writeUTF("da jia hao,cai shi zhen de hao!");

		fs.close();

	}

}

4、读文件

import java.io.IOException;

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;

public class ReadFile {

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

		Configuration conf = new Configuration();

		FileSystem fs = FileSystem.get(conf);

		Path path = new Path("/user/hadoop/data/write.txt");

		if(fs.exists(path)){

			FSDataInputStream is = fs.open(path);

			FileStatus status = fs.getFileStatus(path);

			byte[] buffer = new byte[Integer.parseInt(String.valueOf(status.getLen()))];

			is.readFully(0, buffer);

			is.close();

            fs.close();

            System.out.println(buffer.toString());

		}

	}

}

5、上传本地文件到HDFS

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.Path;

public class CopyFromLocalFile {

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

		Configuration conf = new Configuration();

		FileSystem fs = FileSystem.get(conf);

		Path src = new Path("/home/hadoop/word.txt");

		Path dst = new Path("/user/hadoop/data/");

		fs.copyFromLocalFile(src, dst);

		fs.close();

	}

}

6、删除文件

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.Path;

public class DeleteFile {

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

		Configuration conf = new Configuration();

		FileSystem fs = FileSystem.get(conf);

		Path path = new Path("/user/hadoop/data/word.txt");

		fs.delete(path);

		fs.close();

	}

}

7、获取给定目录下的所有子目录以及子文件

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.FileStatus;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.Path;

public class GetAllChildFile {

	static Configuration conf = new Configuration();

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

		FileSystem fs = FileSystem.get(conf);

		Path path = new Path("/user/hadoop");

		getFile(path,fs);

		//fs.close();

	}

	public static void getFile(Path path,FileSystem fs) throws IOException {

		FileStatus[] fileStatus = fs.listStatus(path);

		for(int i=0;i<fileStatus.length;i++){

			if(fileStatus[i].isDir()){

				Path p = new Path(fileStatus[i].getPath().toString());

				getFile(p,fs);

			}else{

				System.out.println(fileStatus[i].getPath().toString());

			}

		}

	}

}

8、查找某个文件在HDFS集群的位置

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.BlockLocation;

import org.apache.hadoop.fs.FileStatus;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.hdfs.DistributedFileSystem;

import org.apache.hadoop.hdfs.protocol.DatanodeInfo;

public class FindFile {

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

		getFileLocal();

	}

	/**

	 * 查找某个文件在HDFS集群的位置

	 * @Title:

	 * @Description:

	 * @param

	 * @return

	 * @throws

	 */

	public static void getFileLocal() throws IOException{

		Configuration conf = new Configuration();

		FileSystem fs = FileSystem.get(conf);

		Path path = new Path("/user/hadoop/data/write.txt");

		FileStatus status = fs.getFileStatus(path);

		BlockLocation[] locations = fs.getFileBlockLocations(status, 0, status.getLen());

		int length = locations.length;

		for(int i=0;i<length;i++){

			String[] hosts = locations[i].getHosts();

			System.out.println("block_" + i + "_location:" + hosts[i]);

		}

	}

}

9、HDFS集群上所有节点名称信息

package com.hadoop.file;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.BlockLocation;

import org.apache.hadoop.fs.FileStatus;

import org.apache.hadoop.fs.FileSystem;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.hdfs.DistributedFileSystem;

import org.apache.hadoop.hdfs.protocol.DatanodeInfo;

public class FindFile {

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

		getHDFSNode();

	}

	/**

	 * HDFS集群上所有节点名称信息

	 * @Title:

	 * @Description:

	 * @param

	 * @return

	 * @throws

	 */

	public static void getHDFSNode() throws IOException{

		Configuration conf = new Configuration();

		FileSystem fs = FileSystem.get(conf);

		DistributedFileSystem  dfs = (DistributedFileSystem)fs;

		DatanodeInfo[] dataNodeStats = dfs.getDataNodeStats();

		for(int i=0;i<dataNodeStats.length;i++){

			System.out.println("DataNode_" + i + "_Node:" + dataNodeStats[i].getHostName());

		}

	}

}

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