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();
        }
    }
}

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)