hadoop新版本多文件输出
基于Hadoop 1.0.1版本编写，在hadoop 1.0.1 + 版本应该都可以使用
import java.io.IOException;import java.util.StringTokenizer;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.Path;import org.apache.hadoop.io.IntWritable;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.Reducer;import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;import org.apache.hadoop.mapreduce.lib.output.MultipleOutputs;import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;public class MultipleOutputFile{ public static class TokenizerMapper 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 { StringTokenizer itr = new StringTokenizer(value.toString()); while (itr.hasMoreTokens()) { word.set(itr.nextToken()); context.write(word, one); } } } public static class IntSumReducer extends Reducer<Text, IntWritable, Text, IntWritable> { private MultipleOutputs<Text, IntWritable> mos; @Override protected void setup(Context context) throws IOException, InterruptedException { mos = new MultipleOutputs<Text, IntWritable>(context); } private IntWritable result = new IntWritable(); public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException { int sum = 0; for (IntWritable val : values) { sum += val.get(); } result.set(sum); mos.write("text", key, new IntWritable(1)); mos.write("seq", key, result); context.write(key, result); } @Override protected void cleanup(Context context) throws IOException, InterruptedException { // 流操作必须有,否则在数据量小的情况,数据全部停留在缓冲区中 mos.close(); } } public static void main(String[] args) throws IOException, InterruptedException, ClassNotFoundException { Configuration conf = new Configuration(); Job job = new Job(conf, "word count"); FileInputFormat.addInputPaths(job, args[0]); FileOutputFormat.setOutputPath(job, new Path(args[1])); job.setJarByClass(MultipleOutputFile.class); job.setMapperClass(TokenizerMapper.class); job.setReducerClass(IntSumReducer.class); job.setOutputFormatClass(TextOutputFormat.class); MultipleOutputs.addNamedOutput(job, "text", TextOutputFormat.class, Text.class, IntWritable.class); MultipleOutputs.addNamedOutput(job, "seq", TextOutputFormat.class, Text.class, IntWritable.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(IntWritable.class); System.exit(job.waitForCompletion(true) ? 0 : 1); }}?