Question

我正在运行MapReduce程序。我需要以KEYVALUE对的格式给出输入文本文件。所以，如果我写

job.setInputFormatClass(KeyValueTextInputFormat.class);

eclipse编译器显示错误，我无法使用InputFormat。无论如何，我需要将Input的格式设置为KeyValueTextInputFormat 我该怎么做呢？？任何IDea ?????

我的代码是

`

package com.iot.dictionary;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.KeyValueTextInputFormat;
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;


import com.iot.dictionary.Dictionary.AllTranslationsReducer;
import com.iot.dictionary.Dictionary.WordMapper;
public class Driver2 {
public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
    Configuration conf = new Configuration();

        String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
        if (otherArgs.length != 2) {
          System.err.println("Usage: wordcount <in> <out>");
          System.exit(2);
        }
        Job job = new Job(conf, "dictionary");
        System.out.println("Job-> "+job.toString());
        job.setJarByClass(Dictionary.class);
        job.setMapperClass(WordMapper.class);
        job.setReducerClass(AllTranslationsReducer.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);
        job.setInputFormatClass(KeyValueTextInputFormat.class);
        FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
        FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
        System.exit(job.waitForCompletion(true) ? 0 : 1);
    }
}

`

Answer 1

如果您正在使用新的Hadoop API（Hadoop 0.20.2及更高版本），则必须从包org.apache.hadoop.mapreduce.lib.input.KeyValueTextInputFormat中导入KeyValueTextInputFormat.class类，如果您使用的是旧的Hadoop API，你必须从org.apache.hadoop.mapred.KeyValueTextInputFormat中导入它

您在代码中看到该行：

import org.apache.hadoop.mapred.KeyValueTextInputFormat;

将其更改为

import org.apache.hadoop.mapreduce.lib.input.KeyValueTextInputFormat;

希望这有帮助。

由于

在Mapreduce中设置job.setInputFormatClass时出错

1 个答案: