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From Olivier Smadja <osma...@gmail.com>
Subject Appending to a file / updating a file
Date Thu, 28 May 2009 13:46:48 GMT
Hello,

I'm trying hadoop for the first time and I'm just trying to create a file
and append some text in it with the following code:


import java.io.IOException;

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

/**
 * @author olivier
 *
 */
public class HadoopIO {

    public static void main(String[] args) throws IOException {


        String directory = "/Users/olivier/tmp/hadoop-data";
        Configuration conf = new Configuration(true);
        Path path = new Path(directory);
        // Create the File system
        FileSystem fs = path.getFileSystem(conf);
        // Sets the working directory
        fs.setWorkingDirectory(path);

        System.out.println(fs.getWorkingDirectory());

        // Creates a files
        FSDataOutputStream out = fs.create(new Path("test.txt"));
        out.writeBytes("Testing hadoop - first line");
        out.close();
        // then try to append something
        out = fs.append(new Path("test.txt"));
        out.writeBytes("Testing hadoop - second line");
        out.close();

        fs.close();


    }

}


but I receive the following exception:

Exception in thread "main" java.io.IOException: Not supported
    at
org.apache.hadoop.fs.ChecksumFileSystem.append(ChecksumFileSystem.java:290)
    at org.apache.hadoop.fs.FileSystem.append(FileSystem.java:525)
    at com.neodatis.odb.hadoop.HadoopIO.main(HadoopIO.java:38)


1) Can someone tell me what am i doing wrong?

2) How can I update the file (for example, just update the first 10 bytes of
the file)?


Thanks,
Olivier

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