Left join --測試數據

package com.testMr;

import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
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.FileSplit;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.partition.HashPartitioner;

public class LeftJoinDemo {

	public static class LeftJoinMap extends Mapper<LongWritable, Text, Text, Text> {
		@Override
		protected void map(LongWritable key, Text value, Mapper<LongWritable, Text, Text, Text>.Context context)
				throws IOException, InterruptedException {
			String[] arr = value.toString().split(" ");
			FileSplit file = (FileSplit) context.getInputSplit();
			String path = file.getPath().toString();
			String buyer;

			if (path.contains("trade.txt")) {
				buyer = arr[2];
				context.write(new Text(buyer), new Text(value.toString() + " " + "a"));
			} else {
				buyer = arr[1];
				context.write(new Text(buyer), new Text(value.toString() + " " + "b"));
			}
		}
	}

	public static class LeftJoinReduce extends Reducer<Text, Text, Text, Text> {
		@Override
		protected void reduce(Text arg0, Iterable<Text> arg1, Reducer<Text, Text, Text, Text>.Context arg2)
				throws IOException, InterruptedException {

			List<String> a = new ArrayList<String>();
			List<String> b = new ArrayList<String>();
			List<String> result = new LinkedList<String>();
			String[] arr = new String[] {};
			String[] arr1 = new String[] {};
			for (Text line : arg1) {
				arr = line.toString().split(" ");
				if (arr[arr.length - 1].equals("a")) {
					a.add(line.toString());
				} else {
					b.add(line.toString());
				}
			}
			if (a.size() != 0) {
				for(String trade:a){
					arr1 = trade.split(" ");
				}
				if (b.size() != 0) {
					try {
						SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
						Date date;
						Date now = dateFormat.parse("2015-08-02");
						for (String order : b) {
							arr = order.split(" ");
							int price = Integer.parseInt(arr[3]);
							date = dateFormat.parse(arr[4]);
							if (price > 10 && date.before(now)) {
								result.add(arr[0]);
							}
						}
					} catch (NumberFormatException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					} catch (ParseException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
				if (result.contains(arr[0])) {
					arg2.write(arg0, new Text(arr1[1] + " " + arr1[0] + " " +arr1[3]));
				}
			
			}

		}
	}

	public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException, Exception {
		System.out.println(args.length);
		for (String str : args) {
			System.out.println(str);
		}

		String input1 = args[0];
		String input2 = args[1];
		String outputPath = args[2];

		Job job = Job.getInstance();

		job.setJobName("test");
		job.setJarByClass(LeftJoinDemo.class);

		FileInputFormat.addInputPath(job, new Path(input1));
		FileInputFormat.addInputPath(job, new Path(input2));
		FileOutputFormat.setOutputPath(job, new Path(outputPath));

		job.setMapperClass(LeftJoinMap.class);
		job.setReducerClass(LeftJoinReduce.class);
		job.setPartitionerClass(HashPartitioner.class);
		job.setNumReduceTasks(1);

		job.setOutputValueClass(Text.class);
		job.setOutputKeyClass(Text.class);

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

}

trade表
訂單號 賣家 買家 買家城市
1      A    小王   北京
2      B    小李   天津
3      A    小劉   北京


order表  子訂單表
所屬訂單號 買家     商品名稱  價格        發貨時間
1                     小王         電視        12       2015-08-01  09:08:31
1                     小王   冰箱         24      2015-08-01  09:08:14
2                     小李         空調        12       2015-09-02  09:01:31