Thanks. On Fri, Apr 18, 2008 at 9:14 PM, Owen O'Malley <[EMAIL PROTECTED]> wrote:
> > On Apr 17, 2008, at 11:20 PM, Sridhar Raman wrote: > > I am new to MapReduce and Hadoop, and I have managed to find my way > > through > > with a few programs. But I still have some doubts that are constantly > > clinging onto me. I am not too sure whether these are basic doubts, or > > just > > some documentation that I missed somewhere. > > > > Take a look at http://tinyurl.com/4y7776 under InputFormats. > > 1) Should my input _always_ be text files? What if my input is in the > > form > > of Java objects? Where do I handle this conversion? > > > > You can define your own InputFormat that reads an arbitrary format, or use > SequenceFileInputFormat that reads SequenceFiles. SequenceFiles are a file > format defined by Hadoop to hold binary data consisting of Writable keys and > values. > > 2) How do I control how the output is written? For example, if I want > > to > > output in a format that is my own, how do I do it? > > > > That is controlled by the OutputFormat. It defaults to TextOutputFormat, > but you can either use SequenceFileOutputFormat or make your own. > > -- Owen >
