HDFS的Java客户端操作代码(查看HDFS下所有的文件存储位置信息)

1.查看HDFS下所有的文件存储位置信息

 package Hdfs;

 import java.net.URI;
 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;

 public class LocationFile {
     public static void main(String[] args) throws Exception {
         String uri = "hdfs://neusoft-master:9000/user/root/test/demo1";
         Configuration conf = new Configuration();
         try {
             FileSystem fs = FileSystem.get(URI.create(uri), conf);
             Path fpath = new Path(uri);
             FileStatus fileStatus = fs.getFileStatus(fpath);
             BlockLocation[] blockLocations = fs.getFileBlockLocations(
                     fileStatus, 0, fileStatus.getLen());
             int blocklen = blockLocations.length;
             for (int i = 0; i < blocklen; i++) {
                 String[] hosts = blockLocations[i].getHosts();
                 System.out.println("block_" +i+ "_location:" + hosts[0]);
             }
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
 }

HDFS下所有文件存储位置

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)