java - 在Hadoop中使用Mapreduce无法获得预期的减少的输出

我正在尝试学习MapReduce并执行此任务。

我的输入如下(州，体育，金额(美元)):
California Football 69.09California Swimming 31.5Illinois Golf 8.31Illinois Tennis 15.75Oklahoma Golf 15.44Oklahoma Tennis 8.33Texas Golf 16.71Texas Swimming 71.59Washington Football 50.32000000000001
而且，我希望输出的内容能够显示出哪个运动在特定州受欢迎(取决于运动物品的最高销量)。例如:
California Football 69.09Illinois Tennis 15.75Oklahoma Golf 15.44等等

以下是我的Mapper，Reducer和Driver代码:

映射器代码:

package org.assignment.sports;

import java.io.IOException;


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

public class Sports_Mapper2 extends Mapper<LongWritable, Text, Text, Text>{
    public void map(LongWritable key, Text value, Context context)throws IOException, InterruptedException{
        String[] s= value.toString().split(" ");
        String Sport_State = s[0];
        String other = s[1]+" "+s[2];
        context.write(new Text(Sport_State), new Text(other));
    }
}

reducer 代码:

package org.assignment.sports;

import java.io.IOException;

import org.apache.hadoop.io.DoubleWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;


public class Sports_Reducer2 extends Reducer<Text, Text, Text, DoubleWritable>{

    private static double MAX=0.00;
    public void reduce(Text key, Iterable<Text> values, Context context) throws IOException, InterruptedException
    {
        //String[] k= values.toString().split(" ");
        for (Text value:values){
            String[] k= value.toString().split(" ");
            DoubleWritable price = new DoubleWritable(Double.parseDouble(k[1]));
        if(price.get()>MAX){
            MAX = price.get();
        }
        else{
            continue;
        }
        String ss = key.toString()+" "+ k[0];
        context.write(new Text(ss), new DoubleWritable(MAX));
        }
        }

}

驱动程式码:

package org.assignment.sports;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.DoubleWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;

public class Sports_Driver2 {
    public static void main(String[] args) throws Exception
    {
        Configuration conf = new Configuration();

        Job job = new Job(conf, "Sports_Driver2");

        String[] otherArgs =new GenericOptionsParser(conf, args).getRemainingArgs();

        job.setJarByClass(Sports_Driver2.class);
        job.setMapperClass(Sports_Mapper2.class);
        job.setReducerClass(Sports_Reducer2.class);

        job.setMapOutputKeyClass(Text.class);
        job.setMapOutputValueClass(Text.class);

        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(DoubleWritable.class);

        FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
        FileOutputFormat.setOutputPath(job,new Path(otherArgs[1]));

        System.exit(job.waitForCompletion(true)? 0: 1);
    }

}

我得到的输出如下:
California Football 69.09Texas Swimming 71.59
我要去哪里错了？任何帮助表示赞赏

最佳答案

问题是写入每个特定状态后，Reducer中的MAX值未重置。

String ss = key.toString()+" "+ k[0];
context.write(new Text(ss), new DoubleWritable(MAX));
MAX = 0.00;