hadoop自己写的最高温度程序源码

package com.teset;

import java.io.IOException;
import java.util.StringTokenizer;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
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;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

public class Tempreature extends Configured implements Tool {
    // 输入的是行偏移量，一行文本，输出的是 一个年份 最高温度
    public static class TemMapper extends
            Mapper<LongWritable, Text, Text, IntWritable> {

        @Override
        protected void map(LongWritable key, Text value,
                Mapper<LongWritable, Text, Text, IntWritable>.Context context)
                throws IOException, InterruptedException {
            // map处理数据
            String str = value.toString();
            String year = null;
            int Maxtemp = 0;
            StringTokenizer tokenstr = new StringTokenizer(str);
            int i=0;
            while (tokenstr.hasMoreTokens()) {
                String tempstr = tokenstr.nextToken();
                i++;
                if (i==1){
                    year =tempstr;
                    continue;
                }else if (i==5&&Integer.parseInt(tempstr)!=-9999){  
                    int tepMax = Integer.parseInt(tempstr);
                    Maxtemp =Math.max(tepMax, Maxtemp);
                    context.write(new Text(year), new IntWritable(Maxtemp));
                    break;
                }

                }

            }

        }

    public static class TempReducer extends
            Reducer<Text, IntWritable, Text, IntWritable> {

        @Override
        protected void reduce(Text key, Iterable<IntWritable> values,
                Reducer<Text, IntWritable, Text, IntWritable>.Context context)
                throws IOException, InterruptedException {
            int Maxtem = Integer.MIN_VALUE;
            for (IntWritable value:values){
                Maxtem = Math.max(Maxtem, value.get());
            }
            context.write(key, new IntWritable(Maxtem));
        }

    }

    public static void main(String[] args) throws Exception {
        int res = ToolRunner.run(new Configuration(), new Tempreature(), args);
        System.exit(res);
    }

    @Override
    public int run(String[] arg0) throws Exception {
        Configuration conf = getConf();
        Job job = new Job(conf,"MaxTem");//任务名
        job.setJarByClass(Tempreature.class);//指定class
            //输入和输出流
        FileInputFormat.addInputPath(job, new Path(arg0[0]));
        FileOutputFormat.setOutputPath(job, new Path(arg0[1]));    
        job.setMapperClass(TemMapper.class);//map
        job.setReducerClass(TempReducer.class);
        job.setCombinerClass(TempReducer.class);
        job.setOutputValueClass(IntWritable.class);
        job.setOutputKeyClass(Text.class);
        job.waitForCompletion(true);
        return job.isSuccessful()?0:1;

    }

}

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