I think it won't help much, since in a hadoop cluster, people already
allocate "SLOTS" to be the number of cores, supposedly the inherent
parallelism can be already exploited, since different mappers/reducers are
completely independent.
On Wed, Dec 12, 2012 at 2:09 AM, Yu Yang <clouder...@gmail.com> wrote:
> Dears,
>
> I suddenly got this idea to do mapreduce job in a muti-thread way.
> I don't know if it can work. Could anyone give me some advices?
> Here is the java code:
>
>
> import java.io.IOException;
> import org.apache.hadoop.conf.Configuration;
> import org.apache.hadoop.fs.Path;
> import org.apache.hadoop.io.LongWritable;
> import org.apache.hadoop.io.Text;
> import org.apache.hadoop.mapreduce.Job;
> import org.apache.hadoop.mapreduce.Mapper;
> import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
> import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
> import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
> import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
>
> public class LogProcessApp extends Thread {
>
> private static String sep;
> private String x2;
> private String x3;
>
> public LogProcessApp(String arg1,String arg2,String arg3){
> sep=arg1;
> x2=arg2;
> x3=arg3;
> }
>
> public static class CM extends Mapper<LongWritable, Text, Text, Text>{
> private Text keyvar = new Text();
> private Text valvar = new Text();
> public void map(LongWritable key, Text value, Context context)
> throws IOException, InterruptedException {
> String line = value.toString();
> try{
> String data[] = line.split(sep);
> keyvar.set(data[0]);
> valvar.set(data[1]);
> context.write(keyvar,valvar);
> } catch (Exception e) {
> return;
> }
> }
> }
>
> public void run(){
> Configuration conf = new Configuration();
> Job job = null;
> try {
> job = new Job(conf);
> } catch (IOException e1) {
> // TODO Auto-generated catch block
> e1.printStackTrace();
> }
>
> job.setJobName("XXXJob");
> job.setJarByClass(CMR.class);
>
> job.setOutputKeyClass(Text.class);
> job.setOutputValueClass(Text.class);
>
> job.setMapperClass(CM.class);
>
> job.setInputFormatClass(TextInputFormat.class);
> job.setOutputFormatClass(TextOutputFormat.class);
>
> try {
> FileInputFormat.addInputPath(job, new Path(x2));
> } catch (IOException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> }
> FileOutputFormat.setOutputPath(job, new Path(x3));
>
> try {
> job.submit();
> } catch (IOException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> } catch (InterruptedException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> } catch (ClassNotFoundException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> }
>
> }
>
>
> public static void main(String args[]){
> LogProcessApp lpa1=new LogProcessApp(args[0],args[1],args[3]);
> LogProcessApp lpa2=new LogProcessApp(args[4],args[5],args[6]);
> LogProcessApp lpa3=new LogProcessApp(args[7],args[8],args[9]);
> lpa1.start();
> lpa2.start();
> lpa3.start();
> }
> }
>
