Hi Bejoy
1. Old API:
The Map and Reduce classes are the same as in the example, the main
method is as follows
public static void main(String[] args) throws IOException,
InterruptedException {
UserGroupInformation ugi =
UserGroupInformation.createProxyUser("<remote user name>",
UserGroupInformation.getLoginUser());
ugi.doAs(new PrivilegedExceptionAction<Void>() {
public Void run() throws Exception {
JobConf conf = new JobConf(WordCount.class);
conf.setJobName("wordcount");
conf.setOutputKeyClass(Text.class);
conf.setOutputValueClass(IntWritable.class);
conf.setMapperClass(Map.class);
conf.setCombinerClass(Reduce.class);
conf.setReducerClass(Reduce.class);
conf.setInputFormat(TextInputFormat.class);
conf.setOutputFormat(TextOutputFormat.class);
FileInputFormat.setInputPaths(conf, new Path("<path to
input dir>"));
FileOutputFormat.setOutputPath(conf, new Path("<path to
output dir>"));
conf.set("mapred.job.tracker", "<ip:8021>");
FileSystem fs = FileSystem.get(new
URI("hdfs://<ip>:8020"),
new Configuration());
fs.mkdirs(new Path("<remote path>"));
fs.copyFromLocalFile(new Path("<local path>/test.jar"),
new
Path("<remote path>"));
DistributedCache.addArchiveToClassPath(new Path("<remote
path>/test.jar"), conf, fs);
JobClient.runJob(conf);
return null;
}
});
}
It works fine
2. New API:
public class WordCountNewAPI {
public static class WordCountMapper extends Mapper<LongWritable,
Text, Text, IntWritable> {
private final static IntWritable ONE = new IntWritable(1);
private Text word = new Text();
@Override
protected void map(LongWritable key, Text value, Context
context)
throws IOException, InterruptedException {
String line = value.toString();
StringTokenizer tokenizer = new StringTokenizer(line);
while (tokenizer.hasMoreTokens()) {
word.set(tokenizer.nextToken());
context.write(word, ONE);
}
super.map(key, value, context);
}
}
public static class WordCountReducer extends Reducer<Text,
IntWritable, Text, IntWritable> {
@Override
protected void reduce(Text key, Iterable<IntWritable> values,
Context context)
throws IOException, InterruptedException {
int sum = 0;
Iterator<IntWritable> iter = values.iterator();
while (iter.hasNext()) {
sum += iter.next().get();
}
context.write(key, new IntWritable(sum));
super.reduce(key, values, context);
}
}
/**
* @param args
* @throws IOException
* @throws InterruptedException
*/
public static void main(String[] args) throws IOException,
InterruptedException {
UserGroupInformation ugi =
UserGroupInformation.createProxyUser("<remote user name>",
UserGroupInformation.getLoginUser());
ugi.doAs(new PrivilegedExceptionAction<Void>() {
public Void run() throws Exception {
Configuration conf = new Configuration();
conf.set("mapred.job.tracker", "<ip:8021>");
Job job = new Job(conf, "wordcount");
job.setJarByClass(WordCountNewAPI.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
job.setMapperClass(WordCountMapper.class);
job.setCombinerClass(WordCountReducer.class);
job.setReducerClass(WordCountReducer.class);
job.setInputFormatClass(TextInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);
FileInputFormat.setInputPaths(job, new Path("<path to
input dir>"));
FileOutputFormat.setOutputPath(job, new Path("<path to
output dir>"));
FileSystem fs = FileSystem.get(new
URI("hdfs://<ip>:8020"),
new Configuration());
fs.mkdirs(new Path("<remote path>"));
fs.copyFromLocalFile(new Path("<local path>/test.jar"),
new
Path("<remote path>"));
DistributedCache.addArchiveToClassPath(new Path("<remote
path>/test.jar"), conf, fs);
boolean b = job.waitForCompletion(true);
if (!b) {
throw new IOException("error with job!");
}
return null;
}
});
}
}
2011/11/24 Bejoy Ks <[email protected]>:
> Hi Denis
> Unfortunately the mailing lists strips off attachments, So it'd be
> great if you could paste the source in some location and share the url of
> the same. If the source is small enough then please include the same in
> subject body.
>
> For a quick comparison, Try comparing your code with the following sample.
> I just scribbled it long back and it was working
> http://kickstarthadoop.blogspot.com/2011/05/word-count-example-with-hadoop-020.html
>
> Hope it helps!..
>
> Regards
> Bejoy.K.S
>
> On Thu, Nov 24, 2011 at 4:20 PM, Denis Kreis <[email protected]> wrote:
>
>> Hi
>>
>> I' trying to modify the word count example
>> (http://wiki.apache.org/hadoop/WordCount) using the new api
>> (org.apache.hadoop.mapreduce.*). I run the job on a remote
>> pseudo-distributed cluster. It works fine with the old api, but when I
>> using the new one, i'm getting this:
>>
>>
>> 11/11/24 11:28:02 INFO mapred.JobClient: Task Id :
>> attempt_201111241046_0005_m_000000_0, Status : FAILED
>> java.lang.RuntimeException: java.lang.ClassNotFoundException:
>> WordCountNewAPI$WordCountMapper
>> at
>> org.apache.hadoop.conf.Configuration.getClass(Configuration.java:866)
>> at
>> org.apache.hadoop.mapreduce.JobContext.getMapperClass(JobContext.java:199)
>> at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:719)
>> at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
>> at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
>> at java.security.AccessController.doPrivileged(Native Method)
>> at javax.security.auth.Subject.doAs(Subject.java:396)
>> at
>> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1059)
>> at org.apache.hadoop.mapred.Child.main(Child.java:249)
>> Caused by: java.lang.ClassNotFoundException:
>> WordCountNewAPI$WordCountMapper
>> at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
>> at java.security.AccessController.doPrivileged(Native Method)
>> at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
>> at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
>> at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
>> at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
>> at java.lang.Class.forName0(Native Method)
>> at java.lang.Class.forName(Class.java:247)
>> at
>> org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:819)
>> at
>> org.apache.hadoop.conf.Configuration.getClass(Configuration.java:864)
>> ... 8 more
>>
>> The sources are in the attachment
>>
>> Regards
>> Denis
>>
>
