嗨,这是我第一次在 stackoverflow 上提问,我的英语不好。 我已经谷歌了很多次,但仍然没有找到解决我问题的方法。
我的问题是在 Windows 上通过 eclipse 运行名为 wordcount 的 mapreduce 之后。 我有一个文件夹:output\wordcount 但此文件夹中没有任何内容 (后面的图片):
这是我的 WordCount.java
package de.tud.stg;
import org.apache.hadoop.conf.Configuration;
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.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.log4j.BasicConfigurator;
import java.io.IOException;
import java.util.StringTokenizer;
public class WordCount {
public static class WordMapper extends Mapper<Object, Text, Text, IntWritable> {
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
@Override
protected void map(Object key, Text value, Context context) throws IOException, InterruptedException {
StringTokenizer tokenizer = new StringTokenizer(value.toString());
while (tokenizer.hasMoreTokens()) {
word.set(tokenizer.nextToken());
context.write(word, one);
}
}
}
public static class IntSumReducer extends Reducer<Text, IntWritable, Text, IntWritable> {
private IntWritable result = new IntWritable();
@Override
protected void reduce(Text key, Iterable<IntWritable> values, Context context)
throws IOException, InterruptedException {
int sum = 0;
for (IntWritable val : values) {
sum += val.get();
}
result.set(sum);
context.write(key, result);
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
Job job = Job.getInstance(conf, "WordCount");
job.setJarByClass(WordCount.class);
job.setMapperClass(WordMapper.class);
job.setReducerClass(IntSumReducer.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
System.exit(job.waitForCompletion(true)? 0 : 1);
}
}
这是我的 pom.xml 文件
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>de.tud.stg</groupId>
<artifactId>hadoop</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>2.7.2</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-mapreduce-client-common</artifactId>
<version>2.7.2</version>
</dependency>
</dependencies>
</project>
在此之前我有一个错误。我通过链接中的解决方案解决了这个问题: https://sparkbyexamples.com/spark/spark-hadoop-exception-in-thread-main-java-lang-unsatisfiedlinkerror-org-apache-hadoop-io-nativeio-nativeiowindows-access0ljava-lang-stringiz/
我也遇到了一个问题并通过这个解决了: 在这里输入链接描述
然后我有这个问题。 我认为问题来自: job.waitForCompletion(true) 返回假值
非常感谢您的帮助
*更新我的输入文件:
*更新我的输入、输出参数: