1.查看HDFS下所有的文件存储位置信息

1 package Hdfs; 2  3 import java.net.URI; 4 import org.apache.hadoop.conf.Configuration; 5 import org.apache.hadoop.fs.BlockLocation; 6 import org.apache.hadoop.fs.FileStatus; 7 import org.apache.hadoop.fs.FileSystem; 8 import org.apache.hadoop.fs.Path; 9 10 public class LocationFile {11     public static void main(String[] args) throws Exception {12         String uri = "hdfs://neusoft-master:9000/user/root/test/demo1";13         Configuration conf = new Configuration();14         try {15             FileSystem fs = FileSystem.get(URI.create(uri), conf);16             Path fpath = new Path(uri);17             FileStatus fileStatus = fs.getFileStatus(fpath);18             BlockLocation[] blockLocations = fs.getFileBlockLocations(19                     fileStatus, 0, fileStatus.getLen());20             int blocklen = blockLocations.length;21             for (int i = 0; i < blocklen; i++) {22                 String[] hosts = blockLocations[i].getHosts();23                 System.out.println("block_" +i+ "_location:" + hosts[0]);24             }25         } catch (Exception e) {26             e.printStackTrace();27         }28     }29 }

2.提交jar包，并分析运行结果

3.这里的显示结果：

     block_0_location:neusoft-master

  分别为：块号：主机名，因为HDFS的文件是由Data块完成的，Hadoop中得block块一般64M

Hadoop2中block块为128M。(单独分析block块)