希望对您有所帮助
import java.io.File;import org.apache.commons.io.FileUtils;import org.apache.hadoop.conf.Configured;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.output.FileOutputFormat;import org.apache.hadoop.util.Tool;import org.apache.hadoop.util.ToolRunner;public class MapReduceExample extends Configured implements Tool { static class MyMapper extends Mapper<LongWritable, Text, LongWritable, Text> { public MyMapper(){ } protected void map( LongWritable key, Text value, org.apache.hadoop.mapreduce.Mapper<LongWritable, Text, LongWritable, Text>.Context context) throws java.io.IOException, InterruptedException { context.getCounter("mygroup", "jeff").increment(1); context.write(key, value); }; } @Override public int run(String[] args) throws Exception { Job job = new Job(); job.setMapperClass(MyMapper.class); FileInputFormat.setInputPaths(job, new Path(args[0])); FileOutputFormat.setOutputPath(job, new Path(args[1])); job.waitForCompletion(true); return 0; } public static void main(String[] args) throws Exception { FileUtils.deleteDirectory(new File("data/output")); args = new String[] { "data/input", "data/output" }; ToolRunner.run(new MapReduceExample(), args); }}
