hadoop 2 cachefile 分布式缓存 和 Configuration set get 的用法

package com.wc;import java.io.BufferedReader;import java.io.FileReader;import java.io.IOException;import java.net.URI;import java.util.HashSet;import java.util.Set;import java.util.StringTokenizer;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.FileSystem;import org.apache.hadoop.fs.Path;import org.apache.hadoop.io.IntWritable;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.util.GenericOptionsParser;import org.slf4j.Logger;import org.slf4j.LoggerFactory;public class WordCount {public static class TokenizerMapper extendsMapper<Object, Text, Text, IntWritable> {Logger logger=LoggerFactory.getLogger(TokenizerMapper.class);private final static IntWritable one = new IntWritable(1);private Text word = new Text();private Set<String> set; private FileSystem hdfs;@Overrideprotected void setup(org.apache.hadoop.mapreduce.Mapper.Context context)throws IOException, InterruptedException {super.setup(context);set=new HashSet<String>(); Configuration conf = context.getConfiguration();logger.warn("welcome :"+conf.get("welcome"));URI[] patternsURIs = Job.getInstance(conf).getCacheFiles();    Path patternsPath = new Path(patternsURIs[0].getPath());    String patternsFileName = patternsPath.getName().toString();    logger.warn("patternsFileName :"+patternsFileName);BufferedReader br=new BufferedReader(new FileReader(patternsFileName));String line=null;while((line=br.readLine())!=null){logger.warn("line :"+line);line=line.trim();set.add(line);}}  // value已经是文件内容的一行public void map(Object key, Text value, Context context)throws IOException, InterruptedException {StringTokenizer itr = new StringTokenizer(value.toString());while (itr.hasMoreTokens()) {String token = itr.nextToken();if(set.contains(word.toString())){token+="ThisIsACachedWord";}word.set(token);context.write(word, one);logger.warn("the word is :"+word);}}}public static class IntSumReducer extendsReducer<Text, IntWritable, Text, IntWritable> {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);Logger logger=LoggerFactory.getLogger(TokenizerMapper.class);logger.warn("the sum is :" + sum);context.write(key, result);}}public static void main(String[] args) throws Exception {Configuration conf = new Configuration();String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();//Job job = new Job(conf, "word count");conf.set("welcome", "hello HI");Job job = Job.getInstance(conf, WordCount.class.getName());job.addCacheFile(new Path(args[2]).toUri());job.setJarByClass(WordCount.class);job.setMapperClass(TokenizerMapper.class);job.setCombinerClass(IntSumReducer.class);job.setReducerClass(IntSumReducer.class);job.setOutputKeyClass(Text.class);job.setOutputValueClass(IntWritable.class);FileInputFormat.addInputPath(job, new Path(otherArgs[0]));FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));System.exit(job.waitForCompletion(true) ? 0 : 1);}}