MapReduce- 数据的排序处理

                            MapReduce- 数据的排序处理

package com.huhu.day02;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import org.apache.hadoop.io.WritableComparable;

/**
 * 6 9
 * 3 8
 * 4 8
 * 1 0
 * 3 0
 * 8 8
 * 6 7
 * 第一列升序，第二列降序
 * @author huhu_k
 *
 */
public class Number implements WritableComparable<Number> {

	private int first;
	private int second;

	// private int third;
	public Number() {
		super();
	}

	public Number(int first, int second) {
		super();
		this.first = first;
		this.second = second;
	}

	public int getFirst() {
		return first;
	}

	public void setFirst(int first) {
		this.first = first;
	}

	public int getSecond() {
		return second;
	}

	public void setSecond(int second) {
		this.second = second;
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + first;
		result = prime * result + second;
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Number other = (Number) obj;
		if (first != other.first)
			return false;
		if (second != other.second)
			return false;
		return true;
	}

	@Override
	public String toString() {
		return "Number [first=" + first + ", second=" + second + "]";
	}

	@Override
	public void readFields(DataInput in) throws IOException {
		this.first = in.readInt();
		this.second = in.readInt();
	}

	@Override
	public void write(DataOutput out) throws IOException {
		out.writeInt(this.first);
		out.writeInt(this.second);
	}

	@Override
	public int compareTo(Number o) {
		if (this.first== o.first) {
			//第二行数据降序
			return o.second - this.second;
		}
		//第一行升序
		return this.first - o.first;
	}

}

package com.huhu.day02;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
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;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

public class NumericSorting extends ToolRunner implements Tool {

	public static class MyMapper extends Mapper<LongWritable, Text, Number, NullWritable> {

		@Override
		protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
			String[] line = value.toString().split(" ");
			Number number = null;
			if (line.length == 2) {
				number = new Number(Integer.parseInt(line[0]), Integer.parseInt(line[1]));
			}
			context.write(number, NullWritable.get());
		}
	}

	public static class MyReduce extends Reducer<Number, NullWritable, Number, Text> {
		@Override
		protected void reduce(Number key, Iterable<NullWritable> values, Context context)
				throws IOException, InterruptedException {
			for (NullWritable n : values) {
				context.write(key, new Text("---"));
			}
		}
	}

	@Override
	public Configuration getConf() {
		return new Configuration();
	}

	@Override
	public void setConf(Configuration arg0) {

	}

	@Override
	public int run(String[] other) throws Exception {

		Job job = Job.getInstance(getConf(), "NumbericSorting");
		job.setJarByClass(NumericSorting.class);
		job.setMapperClass(MyMapper.class);
		job.setMapOutputKeyClass(Number.class);
		job.setMapOutputValueClass(NullWritable.class);

		job.setReducerClass(MyReduce.class);
		job.setOutputKeyClass(Number.class);
		job.setOutputValueClass(Text.class);

		FileInputFormat.addInputPath(job, new Path(other[0]));
		FileOutputFormat.setOutputPath(job, new Path(other[1]));

		return job.waitForCompletion(true) ? 0 : 1;
	}

	public static void main(String[] args) throws Exception {
		Configuration conf = new Configuration();
		String[] other = new GenericOptionsParser(conf, args).getRemainingArgs();
		if (other.length != 2) {
			System.out.println("your input args number is fail,you need input <in> and <out>");
			System.exit(0);
		}
		ToolRunner.run(conf, new NumericSorting(), other);
	}
}

运行结果：