每日總結

Mapreduce執行個體——排序

依賴：

<dependency>

      <groupId>org.apache.hadoop</groupId>

      <artifactId>hadoop-common</artifactId>

      <version>3.2.0</version>

    </dependency>

    <dependency>

      <artifactId>hadoop-mapreduce-client-app</artifactId>

      <artifactId>hadoop-hdfs</artifactId>

      <groupId>org.slf4j</groupId>

      <artifactId>slf4j-log4j12</artifactId>

      <version>1.7.30</version>

      <artifactId>hadoop-client</artifactId>

</dependency>

實驗代碼：

package  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.input.TextInputFormat;    

import  org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;    

import  org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;    

public  class  OneSort {

    public static class Map extends Mapper<Object, Text, IntWritable, Text> {

        private static Text goods = new Text();

        private static IntWritable num = new IntWritable();

        public void map(Object key, Text value, Context context) throws IOException, InterruptedException {

            String line = value.toString();

            String arr[] = line.split("\t");

            num.set(Integer.parseInt(arr[1]));

            goods.set(arr[0]);

            context.write(num, goods);

        }

    }

    public static class Reduce extends Reducer<IntWritable, Text, IntWritable, Text> {

        private static IntWritable result = new IntWritable();

        public void reduce(IntWritable key, Iterable<Text> values, Context context) throws IOException, InterruptedException {

            for (Text val : values) {

                context.write(key, val);

            }

    public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {

        Configuration conf = new Configuration();

        Job job = new Job(conf, "OneSort");

        job.setJarByClass(OneSort.class);

        job.setMapperClass(Map.class);

        job.setReducerClass(Reduce.class);

        job.setOutputKeyClass(IntWritable.class);

        job.setOutputValueClass(Text.class);

        job.setInputFormatClass(TextInputFormat.class);

        job.setOutputFormatClass(TextOutputFormat.class);

        Path in = new Path("hdfs://hadoop102:8020/mymapreduce2/in/goods_visit1");

        Path out = new Path("hdfs://hadoop102:8020/mymapreduce2/out2");

        FileInputFormat.addInputPath(job, in);

        FileOutputFormat.setOutputPath(job, out);

        System.exit(job.waitForCompletion(true) ? 0 : 1);

}