关于#java#的问题：利用IDEA编写mapreduce程序，统计一篇英文文章各个单词出现次数

利用IDEA编写mapreduce程序，统计一篇英文文章各个单词出现次数，并将结果输出到linux本地（/home/usr这种），输出结果格式为 （单词）出现次数为（ ）次

按照图片中的写法，试一下！

```java
Mapper 
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import java.io.IOException;

public class WordCountMap extends Mapper<LongWritable, Text,Text,IntWritable> {
    Text text=new Text();
    IntWritable intWritable=new IntWritable(1);

    @Override
    protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
        String[] s = value.toString().split(" ");
        for(String word :s ){
            text.set(word);
            context.write(text,intWritable);
        }
    }
}
Reducer
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;

import java.io.IOException;

public class WordCountReduce extends Reducer<Text, IntWritable,Text, IntWritable> {
    int sum;
    IntWritable intWritable=new IntWritable();
    @Override
    protected void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException {
        sum=0;
        for (IntWritable i:values){
            sum+= i.get();
        }
        intWritable.set(sum);
        context.write(key,intWritable);
    }
}
Driver
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
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;


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

        Job job= Job.getInstance(con);

        job.setJarByClass(WordCountDriver.class);

        job.setMapperClass(WordCountMap.class);
        job.setMapOutputKeyClass(Text.class);
        job.setMapOutputValueClass(IntWritable.class);

        job.setReducerClass(WordCountReduce.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);

        FileInputFormat.setInputPaths(job,new Path("in/word.txt"));
        FileOutputFormat.setOutputPath(job,new Path("in/outWord.txt"));

        FileSystem fileSystem=FileSystem.get(new Path("in/outWord.txt").toUri(),con);
        if(fileSystem.exists(new Path("in/outWord.txt"))){
            fileSystem.delete(new Path("in/outWord.txt"),true);
        }

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

输入输出的文件路径在当前项目下建既可

```

代码发出来看看

是要实现这个功能吗

如何编写一个MapReduce程序统计每个单词出现次数
https://blog.csdn.net/weixin_46005650/article/details/123865709