编写MaxTemperature测试用例

(1) 源代码

package cn.edu.xjtu.temperature;import java.io.IOException;import org.apache.hadoop.fs.Path;import org.apache.hadoop.io.IntWritable;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.output.FileOutputFormat;public class MaxTemperature {static class MaxTemperatureMapper extends Mapper<LongWritable, Text, Text, IntWritable> {private static final int MISSING = 9999;public void map(LongWritable key, Text value, Context context)throws IOException, InterruptedException{String line = value.toString();String year = line.substring(15, 19);System.out.println(year);int airTemperature;if(line.charAt(40) == '+'){airTemperature = Integer.parseInt(line.substring(41,45));}else{airTemperature = Integer.parseInt(line.substring(40,45));}String quality = line.substring(45,46);if(airTemperature != MISSING && quality.matches("[01459]")){context.write(new Text(year), new IntWritable(airTemperature));}}}static class MaxTemperatureReducer extendsReducer<Text, IntWritable, Text, IntWritable> {public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException {int maxValue = Integer.MIN_VALUE;for(IntWritable value : values){maxValue = Math.max(maxValue, value.get());}context.write(key, new IntWritable(maxValue));}}public static void main(String[] args) throws Exception {if(args.length != 2){System.err.println("Usage: MaxTemperature <input path> <output path>");System.exit(-1);}Job job = new Job();                  job.setJarByClass(MaxTemperature.class);FileInputFormat.addInputPath(job, new Path(args[0]));FileOutputFormat.setOutputPath(job, new Path(args[1]));job.setMapperClass(MaxTemperatureMapper.class);job.setCombinerClass(MaxTemperatureReducer.class);job.setReducerClass(MaxTemperatureReducer.class);job.setOutputKeyClass(Text.class);job.setOutputValueClass(IntWritable.class);System.exit(job.waitForCompletion(true)? 0 : 1);}}

2. 测试数据 record.txt，传到node14

0067011990999991950051507004...9999999N9+00001+99999999999...0043011990999991950051512004...9999999N9+00221+99999999999...0043011990999991950051518004...9999999N9-00111+99999999999...0043012650999991949032412004...0500001N9+01111+99999999999...0043012650999991949032418004...0500001N9+00781+99999999999...

3. 从eclipse中export出 maxTemperature.jar，传到node14

4. 执行

      (1) [hadoop@node14 app]$ hadoop fs -put record.txt input.txt

      (2) [hadoop@node14 app]$ hadoop jar maxTemperature.jar cn.edu.xjtu.temperature.MaxTemperature input.txt outputDir

      (3) 查看执行结果

             [hadoop@node14 app]$ hadoop fs -ls outputDir

             [hadoop@node14 app]$ hadoop fs -cat outputDir/part-r-00000

             1949    111
             1950    22