hadoop mapreduce 计算平均气温的代码,绝对原创
1901 46
1902 21
1903 48
1904 33
1905 43
1906 47
1907 31
1908 28
1909 26
1910 35
1911 30
1912 16
1913 29
1914 29
1915 5
1916 21
1917 22
1918 31
1919 27
1920 43
1921 34
1922 27
1923 26
以上为结果
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.FloatWritable;
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 AvgTemprature extends Configured implements Tool {
public static class AvgMapper 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 temprature = 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) {
temprature = Integer.parseInt(tempstr);
context.write(new Text(year), new IntWritable(temprature));
break;
}
}
}
}
public static class AvgReducer 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 sum=0;
int count=0;
for (IntWritable value : values) {
sum=sum+value.get();
count++;
}
if (count!=0){
context.write(key, new IntWritable(sum/count));
}
}
}
public static void main(String[] args) throws Exception {
int res = ToolRunner.run(new Configuration(), new AvgTemprature(), args);
System.exit(res);
}
@Override
public int run(String[] arg0) throws Exception {
Configuration conf = getConf();
Job job = new Job(conf, "AvgTem");// 任务名
job.setJarByClass(AvgTemprature.class);// 指定class
// 输入和输出流
job.setMapperClass(AvgMapper.class);// map
job.setReducerClass(AvgReducer.class);
FileInputFormat.addInputPath(job, new Path(arg0[0]));
FileOutputFormat.setOutputPath(job, new Path(arg0[1]));
job.setCombinerClass(AvgReducer.class);
job.setOutputValueClass(IntWritable.class);
job.setOutputKeyClass(Text.class);
job.waitForCompletion(true);
return job.isSuccessful() ? 0 : 1;
}
}
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posted on 2015-05-23 16:25 MrCharles在cnblogs 阅读(649) 评论(0) 编辑 收藏 举报