新版MapReduce的API编程简单模板

import java.io.IOException;import java.util.*;import org.apache.hadoop.conf.*;import org.apache.hadoop.fs.Path;import org.apache.hadoop.io.*;import org.apache.hadoop.mapreduce.*;import org.apache.hadoop.mapreduce.lib.input.*;import org.apache.hadoop.mapreduce.lib.output.*;import org.apache.hadoop.util.*;public class MyJob extends Configured implements Tool{    public static class Map extends Mapper<LongWritable, Text, Text, IntWritable> {        private final static IntWritable one = new IntWritable(1);        private Text word = new Text();        public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {            String line = value.toString();            StringTokenizer tokenizer = new StringTokenizer(line," \t\n\r\f,.:?![]'`;");            while (tokenizer.hasMoreTokens()) {                word.set(tokenizer.nextToken());               context.write(word, one);            }        }     }    public static class Reduce extends Reducer<Text, IntWritable, Text, IntWritable> {         public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException {             int sum = 0;             while (values.iterator().hasNext()) {                 sum += values.iterator().next().get();             }             context.write(key, new IntWritable(sum));         }    }        public int run(String[] args) throws Exception {    Configuration conf=getConf();            Job  job= new Job(conf,"WordCount");        job.setJarByClass(MyJob.class);                FileInputFormat.setInputPaths(job, new Path(args[0]));        FileOutputFormat.setOutputPath(job, new Path(args[1]));                job.setJobName("WordCount");        job.setMapperClass(Map.class);        job.setCombinerClass(Reduce.class);        job.setReducerClass(Reduce.class);                 job.setInputFormatClass(TextInputFormat.class);         job.setOutputFormatClass(TextOutputFormat.class);         job.setOutputKeyClass(Text.class);         job.setOutputValueClass(IntWritable.class);        System.exit(job.waitForCompletion(true)?0:1) ;         return 1;    }        public static void main(String[] args) throws Exception {        int res =ToolRunner.run(new Configuration(), new MyJob(), args);        System.exit(res);    }}