Hadoop HDFS文件操作的Java代码

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());    }       }        }