要求：和前一篇的要求正好相反。。
在HDFS中生成一个130KB的文件：
代码如下：
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import java.net.URI;
import org.apache.hadoop.fs.FileSystem;
import java.io.OutputStream;
import org.apache.hadoop.fs.Path;
public class ShenChenHDFS {
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
String uri = args[0];
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(URI.create(uri), conf);
OutputStream os=fs.create(new Path(uri));
byte[] bytes=new byte[130];
for (int i = 0; i < bytes.length; i++) {
bytes[i]=(byte) i;
}
os.write(bytes);
}
}
运行的结果：
代码如下：
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.fs.Path;
import java.net.URI;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.conf.Configuration;
public class CopyHDFSToLocal {
public static void main(String[] args) throws IOException {
String uri = args[0];
Configuration conf = new Configuration();
FileSystem fs = FileSystem.get(URI.create(uri), conf);
InputStream in = in = fs.open(new Path(uri));
File file=new File("/home/weiguohui/shengcheng_hdfs_to_local.txt");
FileOutputStream fos=new FileOutputStream(file);
byte[] bytes=new byte[1024];
int offset=100;
int len=20;
int numberRead=0;
while((numberRead=in.read(bytes))!=-1){
fos.write(bytes, 100, 20);
}
IOUtils.closeStream(in);
IOUtils.closeStream(fos);
}
}