You are mixing old mapred calls with new mapreduce calls.
Please look for a sample with the following structure:
@Override
public void map(Text key, Writable value,
Context context)
...
context.write(key, objWrite);
On Sun, Apr 25, 2010 at 5:12 PM, iman453 <[email protected]> wrote:
>
> Hi,
>
> I just started playing around with Hadoop, and am running into an error
> while running my first basic program. The error is:
>
> java.io.IOException: Type mismatch in key from map: expected
> org.apache.hadoop.io.Text, recieved org.apache.hadoop.io.LongWritable
> at
> org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:845).
>
> I've pasted the MapReduce program I'm trying to run below. I'd really
> appreciate any help I could get.
>
> import java.io.IOException;
> import java.util.Iterator;
> import java.util.StringTokenizer;
>
> import org.apache.hadoop.io.LongWritable;
> import org.apache.hadoop.io.Text;
> import org.apache.hadoop.mapred.OutputCollector;
> import org.apache.hadoop.mapred.Reporter;
> import org.apache.hadoop.mapred.TextInputFormat;
> import org.apache.hadoop.mapreduce.Mapper;
>
> import java.io.IOException;
> import java.util.StringTokenizer;
>
> import org.apache.hadoop.conf.Configuration;
> import org.apache.hadoop.conf.Configured;
> import org.apache.hadoop.fs.Path;
> import org.apache.hadoop.io.LongWritable;
> import org.apache.hadoop.io.IntWritable;
> import org.apache.hadoop.io.Text;
> import org.apache.hadoop.mapred.OutputCollector;
> import org.apache.hadoop.mapred.Reporter;
> //import org.apache.hadoop.mapreduce.InputFormat;
> import org.apache.hadoop.mapreduce.Job;
> import org.apache.hadoop.mapreduce.Mapper;
> import org.apache.hadoop.mapreduce.OutputFormat;
> import org.apache.hadoop.mapreduce.Reducer;
> import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
> import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
> import org.apache.hadoop.util.GenericOptionsParser;
> import org.apache.hadoop.util.Tool;
> import org.apache.hadoop.util.ToolRunner;
>
> public class Rating extends Configured implements Tool {
> public static class RatingMapper extends Mapper<Object, Text, Text,
> Text> {
>
> private final Text rating = new Text();
> private final Text movie = new Text();
>
> public void map(Object key, Text val,
> OutputCollector<Text, Text> output, Reporter
> reporter)
> throws IOException, InterruptedException {
>
> String line = val.toString();
>
> if (!line.contains("{")) {
> StringTokenizer itr = new
> StringTokenizer(line);
> String garbage = itr.nextToken();
> garbage = itr.nextToken();
> String ratingString = itr.nextToken();
> //Integer ratingInt =
> Integer.parseInt(ratingString);
> // String ratingString2 = ratingInt.toString();
> rating.set(ratingString);
>
> StringTokenizer itr2 = new
> StringTokenizer(line);
> garbage = itr.nextToken("\"");
> String movieString = itr.nextToken();
> movie.set(movieString);
> output.collect(rating, movie);
> }
>
> }
> }
>
> public static class RatingReducer extends Reducer<Text, Text, Text,
> Text> {
>
> public void reduce(Text key, Iterator<Text> values,
> OutputCollector<Text, Text> output, Reporter
> reporter)
> throws IOException {
>
> boolean first = true;
> StringBuilder toReturn = new StringBuilder();
> while (values.hasNext()) {
> if (!first)
> toReturn.append(", ");
> first = false;
> toReturn.append(values.next().toString());
> }
>
> String keyString = "Movies above " + key.toString()
> + "-";
> key.set(keyString);
> output.collect(key, new Text(toReturn.toString()));
> }
>
> }
>
> // public class RatingDriver {
>
> public int run(String[] args) throws Exception {
> Configuration conf = new Configuration();
>
> String[] otherArgs = new GenericOptionsParser(conf, args)
> .getRemainingArgs();
> if (otherArgs.length != 2) {
> System.err.println("Usage: wordcount <in> <out>");
> System.exit(2);
> }
>
> Job job;
> try {
> job = new Job(conf, "IMDB");
>
> job.setJarByClass(Rating.class);
> job.setMapperClass(RatingMapper.class);
> // job.setCombinerClass(IntSumReducer.class);
> job.setReducerClass(RatingReducer.class);
> job.setOutputKeyClass(Text.class);
> job.setOutputValueClass(Text.class);
> job.setMapOutputKeyClass(Text.class);
> job.setMapOutputValueClass(Text.class);
> // job.setInputFormatClass(TextInputFormat.class);
> // job.setOutputFormatClass((Class<? extends
> OutputFormat>)
> TextInputFormat.class);
> try {
> // FileInputFormat.addInputPath(job,
> new
> Path("/tmp/hadoop-ishan/dfs/input"));
> FileInputFormat.addInputPath(job, new
> Path(otherArgs[0]));
> } catch (IOException e) {
> }
> // FileOutputFormat.setOutputPath(job, new
> Path("/tmp/hadoop-ishan/dfs/output"));
> FileOutputFormat.setOutputPath(job, new
> Path(otherArgs[1]));
> try {
> System.exit(job.waitForCompletion(true) ? 0
> : 1);
> } catch (IOException e) {
> } catch (InterruptedException e) {
> } catch (ClassNotFoundException e) {
> }
> } catch (IOException e1) {
> }
> return 1;
> }
>
> public static void main(String[] args) throws Exception {
> int res = ToolRunner.run(new Configuration(), new Rating(),
> args);
> System.exit(res);
> }
>
> // }
> }
> --
> View this message in context:
> http://old.nabble.com/Type-mismatch-in-key-from-map-tp28359780p28359780.html
> Sent from the HBase User mailing list archive at Nabble.com.
>
>
