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Date: Tue, 13 Apr 2010 09:13:45 +0800
From: "Lurga" <lurga.lee@gmail.com>
To: "avro-user" <avro-user@hadoop.apache.org>
Subject: Question on writing/reading file with different schema
Message-ID: <201004130913432506688@gmail.com>
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Hello,
I create a "Person" record (3 fields: first,last,age), and an "Extract" record (2 fields: first,last). Then I use "Person" to write some object to a file. When I use "Extract" to read data from the file, I got an exception: Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -14.
It seems like GenericDatumReader.readRecord won't skip the last fields. How can I read the data corretly?

My code is below:
public void browseName() throws IOException {
  List<Field> fields = new ArrayList<Field>();
  fields.add(new Field("First", Schema.create(Type.STRING), null, null));
  fields.add(new Field("Last", Schema.create(Type.STRING), null, null)); 
  Schema extractSchema = Schema.createRecord(fields);
  DataFileReader<Record> reader = new DataFileReader<Record>(new File(
    fileName), new GenericDatumReader<Record>(extractSchema));
  try {
    while (reader.hasNext()) {
      Record person = reader.next();
      System.out.print(person.get("First").toString() + " " + person.get("Last").toString() + "\t");
    }
  } finally {
    reader.close();
  }
}

Regards,

2010-04-13 


Lurga