mapreduce-查找最高气温的Mapper类

package com;


import java.io.IOException;


import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;


public class MaxTemperatureMapper extends Mapper<LongWritable, Text, Text, IntWritable> {


private static final int MISSING = 9999;

@Override 
public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException{
String line = value.toString();
String year = line.substring(15, 19);
int airTemperature;
if(line.charAt(87) == '+'){
airTemperature = Integer.parseInt(line.substring(88, 92));

}else{
airTemperature = Integer.parseInt(line.substring(87, 92));
}
String quality = line.substring(92, 93);
if(airTemperature != MISSING && quality.matches("[01459]")){
context.write(new Text(year), new IntWritable(airTemperature));
}
}
}