Hadoop学习之第四章节：最高温度统计测试程序
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;
publicclass MinTemperatureMapper extends Mapper{
privatestatic final intMISSING = 9999;
@Override
publicvoid 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("")) {
context.write(new Text(year), new IntWritable(airTemperature));
}
}
}
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