KeyValueTextInputFormat实例

package inputformat;import java.net.URI;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.FileSystem;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.KeyValueLineRecordReader;import org.apache.hadoop.mapreduce.lib.input.KeyValueTextInputFormat;import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;/** * helloyouhelloyou * hellome * */public class MyKeyValueTextInputFormatApp {private static final String INPUT_PATH = "hdfs://chaoren1:9000/hello";private static final String OUT_PATH = "hdfs://chaoren1:9000/out";public static void main(String[] args) throws Exception{Configuration conf = new Configuration();                //使用特定的分割符分开conf.set(KeyValueLineRecordReader.KEY_VALUE_SEPERATOR, "\t");final FileSystem filesystem = FileSystem.get(new URI(OUT_PATH), conf);filesystem.delete(new Path(OUT_PATH), true);final Job job = new Job(conf , MyKeyValueTextInputFormatApp.class.getSimpleName());job.setJarByClass(MyKeyValueTextInputFormatApp.class);FileInputFormat.setInputPaths(job, INPUT_PATH);job.setInputFormatClass(KeyValueTextInputFormat.class);job.setMapperClass(MyMapper.class);job.setMapOutputKeyClass(Text.class);job.setMapOutputValueClass(LongWritable.class);job.setNumReduceTasks(0);job.setOutputKeyClass(Text.class);job.setOutputValueClass(LongWritable.class);FileOutputFormat.setOutputPath(job, new Path(OUT_PATH));job.waitForCompletion(true);}public static class MyMapper extends Mapper<Text, Text, Text, LongWritable>{protected void map(Text key, Text value, org.apache.hadoop.mapreduce.Mapper<Text,Text,Text,LongWritable>.Context context) throws java.io.IOException ,InterruptedException {context.write(key, new LongWritable(1));context.write(value, new LongWritable(1));};}}