从本地读入部分字节到HDFS当中

本地文件：test.txt

The modern science of networks has brought significant advances to our understanding of complex systems. One of the most relevant features of graphs representing real systems
is community structure, or clustering, i.e. the organization of vertices in clusters, with many edges joining vertices of the same cluster and comparatively few edges joining vertices of different clusters.

Java程序：

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URI;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

public class FileFromLocalToHdfs {

public static void main(String[] args) throws Exception {
String local = args[0];
String dest =args[1];

InputStream in = new BufferedInputStream(new FileInputStream(local));

Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(URI.create(dest), conf);
OutputStream out = fs.create(new Path(dest));

byte [] bytes = new byte [20];
in.skip(100);    //跳过前100个字节
int readNumberOfBytes = in.read(bytes, 0, 20);   //读取第101至120个字节

out.write(bytes);
out.flush();

in.close();
out.close();
}
}

运行结果：