MapReduce程式設計例項(六)
阿新 • • 發佈:2019-01-10
package com.t.hadoop; import java.io.IOException; import java.util.ArrayList; import java.util.List; 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; /** * 多表排序 * @author daT
[email protected] * */ public class MTJoin { public static int times = 1; public static class MTMapper extends Mapper<Object, Text, Text, Text>{ @Override protected void map(Object key, Text value, Context context) throws IOException, InterruptedException { String relation = new String(); String line = value.toString(); if(line.contains("factoryname")||line.contains("addressID")) return; int i = 0; while(line.charAt(i)<'0'||line.charAt(i)>'9'){ i++; } if(i>0){//左表 relation = "1"; context.write(new Text(String.valueOf(line.charAt(i))),new Text(relation + line.substring(0,i-1))); }else{//右表 relation = "2"; context.write(new Text(String.valueOf(line.charAt(i))),new Text(relation +line.substring(i+1))); } } } public static class MTReducer extends Reducer<Text, Text, Text, Text>{ @Override protected void reduce(Text key, Iterable<Text> value,Context context) throws IOException, InterruptedException { if(times==1){ context.write(new Text("factoryName"), new Text("Address")); times ++; } int factoryNum = 0; int addressNum = 0; String[] factorys = new String[10]; String[] addresses = new String[10]; for(Text t:value){ if(t.charAt(0)=='1'){//左表 factorys[factoryNum]=t.toString().substring(1); factoryNum++; }else{//右表 addresses[addressNum]=t.toString().substring(1); addressNum++; } } for(int i = 0;i<factoryNum;i++){ for(int j=0;j<addressNum;j++){ context.write(new Text(factorys[i]), new Text(addresses[j])); } } } } public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException{ Configuration conf = new Configuration(); String[] otherArgs = new GenericOptionsParser(conf,args).getRemainingArgs(); if(otherArgs.length<2){ System.out.println("Parameters error"); System.exit(2); } Job job =new Job(conf,"MTjoin"); job.setJarByClass(MTJoin.class); job.setMapperClass(MTMapper.class); job.setReducerClass(MTReducer.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(Text.class); FileInputFormat.addInputPath(job, new Path(otherArgs[0])); FileOutputFormat.setOutputPath(job, new Path(otherArgs[1])); System.exit(job.waitForCompletion(true)?0:1); } }