package com.shaonaiyi.mapreduce;
import java.io.IOException;
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;
public class accessTimesSort {
    public static class MyMapper extends Mapper<Object, Text, IntWritable, Text> {
        public void map(Object key, Text value, Context context) throws IOException, InterruptedException {
            String lines = value.toString();
            // 按tab键作为分隔符
            String array[] = lines.split("\t");
            // 将访问次数作为key
            int keyOutput = Integer.parseInt(array[1]);
            // 将日期作为value
            String valueOutput = array[0];
            context.write(new IntWritable(keyOutput), new Text(valueOutput));
        }
    }
    public static class MyReducer extends Reducer<IntWritable, Text, Text, IntWritable> {
        public void reduce(IntWritable key, Iterable<Text> values, Context context) throws IOException, InterruptedException {
            for (Text value : values) {
              // 对于IntWritable类型的key，MapReduce会默认进行升序排序
                context.write(value, key);
            }
        }
    }
    public static void main(String[] args) throws Exception {
        Configuration conf = new Configuration();
        String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
        if (otherArgs.length < 2) {
            System.err.println("Usage: wordcount <in> [<in>...] <out>");
            System.exit(2);
        }
        Job job = new Job(conf, "Access Time Sort");
        job.setJarByClass(accessTimesSort.class);
        job.setMapperClass(MyMapper.class);
        job.setReducerClass(MyReducer.class);
        job.setMapOutputKeyClass(IntWritable.class);
        job.setMapOutputValueClass(Text.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);
        for (int i = 0; i < otherArgs.length - 1; ++i) {
            FileInputFormat.addInputPath(job, new Path(otherArgs[i]));
        }
        FileOutputFormat.setOutputPath(job, new Path(otherArgs[otherArgs.length - 1]));
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}