查找某个文件在HDFS集群中的位置

通过"FileSystem.getFileBlockLocation（FileStatus file，long start，long len）"可查找指定文件在HDFS集群上的位置，其中file为文件的完整路径，start和len来标识查找文件的路径。
 
以下是java代码的实现：
 
package com.njupt.Hadoop;
 

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 FindFileOnHDFS {
 

public static void main(String[] args) throws Exception{
 getHDFSNodes();
 getFileLocal();
 }
 

public static void getFileLocal() throws Exception {
 

Configuration conf = new Configuration();
 FileSystem hdfs = FileSystem.get(conf);
 Path fpath = new Path("/user/root/20120722/word.txt");
 
FileStatus fileStatus = hdfs.getFileStatus(fpath);
    BlockLocation[] blkLocations = hdfs.getFileBlockLocations(fileStatus, 0, fileStatus.getLen());
 
  int blockLen = blkLocations.length;
   
    for(int i = 0 ; i < blockLen ; ++i ){
      String[] hosts = blkLocations[i].getHosts();
      System.out.println("block_"+i + "_location:" + hosts[i]);
    }
 }
 

public static void getHDFSNodes() throws Exception{
 Configuration conf = new Configuration();
 FileSystem fs = FileSystem.get(conf);
 DistributedFileSystem hdfs = (DistributedFileSystem)fs;
 DatanodeInfo[] dataNodeStats = hdfs.getDataNodeStats();
 
for( int i = 0 ; i < dataNodeStats.length ; ++i ){
 System.out.println("DataNode_" + i + "_Node:" + dataNodeStats[i].getHostName());
 }
 }
 }