thx very much ,i'll try it
On 12/9/06, Sami Siren [EMAIL PROTECTED] wrote:
吴志敏 wrote:
I want to read the stored segments to a xml file, but when I read the
SegmentReader.java, I find that it 's not a simple thing.
it's a hadoop's job to dump a text file. I just want to dump the
segments' some content witch I interested to a xml.
So some one can tell me hwo to do this, any reply will be appreciated!
Segment data is basically just a bunch of files containing
key-value pairs, so there's always the possibility of reading the data
directly with help of:
http://lucene.apache.org/hadoop/docs/api/org/apache/hadoop/io/SequenceFile.Reader.html
To see what kind of object to expect you can just examine the beginning
of file where there is some metadata stored - like class used for key
and class used for value (that metadata is also available from methods
of SequenceFile.Reader class).
For example to read the contents of Content data from a segment one
could use something like:
SequenceFile.Reader reader = new SequenceFile.Reader(fs, path, conf);
Text url = new Text(); //key
Content content = new Content();//value
while (reader.next(url, content)) {
//now just use url and content the way you like
}
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Sami Siren
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www.babatu.com
