- package com.run.ayena.distributed.test;
- 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.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;
- ////统计文本中指定某个单词出现的次数
- public class SingleWordCount {
- public static class SingleWordCountMapper extends
- Mapper<Object, Text, Text, IntWritable> {
- private final static IntWritable one = new IntWritable(1);
- private Text val = new Text();
- public void map(Object key, Text value, Context context)
- throws IOException, InterruptedException {
- StringTokenizer itr = new StringTokenizer(value.toString());
- String keyword = context.getConfiguration().get("word");
- while (itr.hasMoreTokens()) {
- String nextkey = itr.nextToken();
- if (nextkey.trim().equals(keyword)) {
- val.set(nextkey);
- context.write(val, one);
- } else {
- // do nothing
- }
- }
- }
- }
- public static class SingleWordCountReducer extends
- Reducer<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);
- context.write(key, result);
- }
- }
- public static void main(String[] args) throws Exception {
- Configuration conf = new Configuration();
- String[] otherArgs = new GenericOptionsParser(conf, args)
- .getRemainingArgs();
- if (otherArgs.length != 3) {
- System.err.println("Usage: wordcount ");
- System.exit(2);
- }
- // 输入指定的单词
- conf.set("word", otherArgs[2]);
- // 指定系统路
- conf.set("mapred.system.dir", "/cygdrive/e/workspace_hadoop/SingleWordCount/");
- // 设置运行的job名称
- Job job = new Job(conf, "word count");
- // 设置运行的job类
- job.setJarByClass(SingleWordCount.class);
- // 设置Mapper
- job.setMapperClass(SingleWordCountMapper.class);
- // 设置本地聚合类,该例本地聚合类同Reduer类
- job.setCombinerClass(SingleWordCountReducer.class);
- // 设置Reduer
- job.setReducerClass(SingleWordCountReducer.class);
- // 设置Map的输出
- job.setMapOutputKeyClass(Text.class);
- job.setMapOutputValueClass(IntWritable.class);
- // 设置Reducer输出的key类型
- job.setOutputKeyClass(Text.class);
- // 设置Reducer输出的value类型
- job.setOutputValueClass(IntWritable.class);
- // 设置输入和输出的目录
- FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
- FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
- // 执行,直到结束就退出
- System.exit(job.waitForCompletion(true) ? 0 : 1);
- }
- }
- //该片段来自于http://www.codesnippet.cn/detail/050920135664.html
来源: http://www.codesnippet.cn/detail/050920135664.html