package com.duking.hadoop;

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 Dedup {

	// map将输入中的value复制到输出数据的key上，并直接输出

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

		private static Text line = new Text();// 每行数据

		// 实现map函数

		public void map(Object key, Text value, Context context)

		throws IOException, InterruptedException {

			line = value;

			context.write(line, new Text(""));

		}

	}

	// reduce将输入中的key复制到输出数据的key上，并直接输出    这是数据区重的思想

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

		// 实现reduce函数

		public void reduce(Text key, Iterable<Text> values, Context context)

		throws IOException, InterruptedException {

			context.write(key, new Text(""));

		}

	}

	public static void main(String[] args) throws Exception {

		Configuration conf = new Configuration();

		// 这句话很关键

		conf.set("mapred.job.tracker", "192.168.60.129:9000");

		//指定带运行参数的目录为输入输出目录

		String[] otherArgs = new GenericOptionsParser(conf, args)

		.getRemainingArgs();

		/*      指定工程下的input2为文件输入目录    output2为文件输出目录

		String[] ioArgs = new String[] { "input2", "output2" };

		String[] otherArgs = new GenericOptionsParser(conf, ioArgs)

				.getRemainingArgs();*/

		if (otherArgs.length != 2) {    //判断路径参数是否为2个

			System.err.println("Usage: Data Deduplication <in> <out>");

			System.exit(2);

		}

		//set maprduce job name

		Job job = new Job(conf, "Data Deduplication");

		job.setJarByClass(Dedup.class);

		// 设置Map、Combine和Reduce处理类

		job.setMapperClass(Map.class);

		job.setCombinerClass(Reduce.class);

		job.setReducerClass(Reduce.class);

		// 设置输出类型

		job.setOutputKeyClass(Text.class);

		job.setOutputValueClass(Text.class);

		// 设置输入和输出目录

		FileInputFormat.addInputPath(job, new Path(otherArgs[0]));

		FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));

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

	}

}