[Hadoop-common-user] FW: type mismatch error

hi, all.
I am a new hadoop beginner, I try to construct a map and reduce task to run, however encountered an exception while continue going further.
Exception:
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$MapOutputBuffer.collect(MapTask.java:845)
at org.apache.hadoop.mapred.MapTask$NewOutputCollector.write(MapTask.java:541)
at org.apache.hadoop.mapreduce.TaskInputOutputContext.write(TaskInputOutputContext.java:80)
at org.apache.hadoop.mapreduce.Mapper.map(Mapper.java:124)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:621)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:305)
at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:177)
Mapper:
public class TaskMapper extends Mapper<LongWritable , Text ,Text ,Text>{
public void Map(LongWritable key, Text value, Context context)
{
try {
System.out.println(value.toString());
context.write(new Text(Calendar.getInstance().getTime().toString()),value);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Reducer:
public class TaskReducer extends Reducer<Text , Text ,Text ,Text>{
public void reduce(Text key,Iterable<Text> value, Context context)
{
try {
context.write(key,new Text(value.iterator().hashCode()+""));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}
Main(Entry)
public class TaskEntry extends Configured implements Tool{

@Override
public int run(String[] arg0) throws Exception {
Job job=new Job(getConf());
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(Text.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(Text.class);
//job.setInputFormatClass(KeyValueTextInputFormat.class);
FileInputFormat.addInputPath(job, new Path(arg0[0]));
FileOutputFormat.setOutputPath(job, new Path(arg0[1]));
job.setMapperClass(TaskMapper.class);
job.setReducerClass(TaskReducer.class);
return job.waitForCompletion(true)?0:1;
}
public static void main(String args[]) throws Exception
{
int exitCode=ToolRunner.run(new TaskEntry(), args);
System.exit(exitCode);
}

}


Any help is greatly appreciated!
Thanks in advance.

James, Teng (Teng Linxiao)
eRL, CDC, eBay, Shanghai
Extension: 86-21-28913530
MSN: tenglinxiao@hotmail.com
Skype: James,Teng
Email: xteng@ebay.com
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