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测试数据mons测试数据press.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！" );

     }

}