Hi,
I face another issue, now, Here is my program
public static class MapClass extends Mapper<LongWritable, Text, Text,
LongWritable> {
public void map(LongWritable key, Text value, Context context)
throws IOException, InterruptedException {
// your map code goes here
String[] fields = value.toString().split(",");
Text yearInText = new Text();
LongWritable out = new LongWritable();
String year = fields[1];
String claims = fields[8];
if (claims.length() > 0 && (!claims.startsWith("\""))) {
yearInText.set(year.toString());
out.set(Long.parseLong(claims));
context.write(yearInText, out);
}
}
}
public static class Reduce extends Reducer<Text, LongWritable, Text,
Text> {
public void reduce(Text key, Iterable<LongWritable> values, Context
context) throws IOException, InterruptedException {
// your reduce function goes here
Text value = new Text();
value.set(values.toString());
context.write(key, value);
}
}
public int run(String args[]) throws Exception {
Job job = new Job();
job.setJarByClass(TopKRecord.class);
job.setMapperClass(MapClass.class);
job.setReducerClass(Reduce.class);
FileInputFormat.setInputPaths(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
job.setMapOutputValueClass(LongWritable.class);
job.setJobName("TopKRecord");
// job.setNumReduceTasks(0);
boolean success = job.waitForCompletion(true);
return success ? 0 : 1;
}
public static void main(String args[]) throws Exception {
int ret = ToolRunner.run(new TopKRecord(), args);
System.exit(ret);
}
}
When I run this in hadoop, I see the following error
12/08/02 15:12:59 INFO mapred.JobClient: Task Id :
attempt_201208021025_0011_m_000001_0, Status : FAILED
java.io.IOException: Type mismatch in key from map: expected
org.apache.hadoop.io.LongWritable, recieved org.apache.hadoop.io.Text
at
org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:1014)
at
org.apache.hadoop.mapred.MapTask$NewOutputCollector.write(MapTask.java:691)
at
org.apache.hadoop.mapreduce.TaskInputOutputContext.write(TaskInputOutputContext.java:80)
at com.hadoop.programs.TopKRecord$MapClass.map(TopKRecord.java:39)
at com.hadoop.programs.TopKRecord$MapClass.map(TopKRecord.java:26)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
at org.apache.hadoop.mapred.Child.main(Child.java:249)
I asked this question on SO, and got response that I need to
setMapOutputValue class and I tried that too (see in code above) by
following
http://hadoop.apache.org/common/docs/r0.20.2/api/org/apache/hadoop/mapreduce/Job.html#setMapOutputKeyClass%28java.lang.Class%29
How do I fix this?
Thank you
+ Harit
