myMapper

  1. public class myMapper extends Mapper<LongWritable, Text,Text, IntWritable> {
  2.     Text text = new Text();
  3.     IntWritable vOut =  new IntWritable(1);
  5.     @Override
  6.     protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
  7.         // 切割
  8.         // atguigu
  9.         // atguigu
  10.         String[] s = value.toString().split(" ");
  11.         for (String s1 : s) {
  12.             text.set(s1);
  13.             context.write(text,vOut);
  14.         }
  15.     }
  16. }

myReducer

  1. public class myReducer extends Reducer<Text, IntWritable, Text,IntWritable> {
  2.     IntWritable vFinalOut = new IntWritable();
  3.     @Override
  4.     protected void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException {
  6.         // context将map的结果处理成key和Iterable集合
  7.         // atguigu (1,1)
  9.         int sum = 0;
  10.         for (IntWritable value : values) {
  11.             sum += value.get();
  12.         }
  13.         vFinalOut.set(sum);
  14.         context.write(key,vFinalOut);
  15.     }
  16. }

myDriver

  1. public class myDriver {
  2.     public static void main(String[] args) throws IOException, InterruptedException, ClassNotFoundException {
  4.         Job job = Job.getInstance();
  6.         job.setMapperClass(myMapper.class);
  7.         job.setReducerClass(myReducer.class);
  9.         job.setMapOutputKeyClass(Text.class);
  10.         job.setMapOutputValueClass(IntWritable.class);
  12.         job.setOutputKeyClass(Text.class);
  13.         job.setMapOutputValueClass(IntWritable.class);
  15.         FileInputFormat.setInputPaths(job, new Path("C:\\tmp\\input2\\aa.txt"));
  16.         FileOutputFormat.setOutputPath(job, new Path("C:\\tmp\\output99"));
  18.         //提交任务
  19.         boolean result = job.waitForCompletion(true);
  20.         // 模仿官方文档退出程序
  21.         System.exit(result ? 0 : 1);
  22.     }
  23. }

Debug

image.png
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