我正在尝试执行下面的代码
package test;
import java.io.IOException;
import java.util.*;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.util.*;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
public class Diction {
public static class WordMapper extends Mapper<Text,Text,Text,Text>
{
private Text word = new Text();
public void map(Text key, Text value, Context context) throws IOException, InterruptedException
{
StringTokenizer itr = new StringTokenizer(value.toString(),",");
while (itr.hasMoreTokens())
{
word.set(itr.nextToken());
context.write(key, word);
}
}
}
public static class AllTranslationsReducer
extends Reducer<Text,Text,Text,Text>
{
private Text result = new Text();
public void reduce(Text key, Iterable<Text> values,
Context context
) throws IOException, InterruptedException
{
String translations = "";
for (Text val : values)
{
translations += "|"+val.toString();
}
result.set(translations);
context.write(key, result);
}
}
public static void main(String[] args) throws Exception
{
Configuration conf = new Configuration();
Job job = new Job(conf, "dictionary");
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("/tmp/hadoop-cscarioni/dfs/name/file"));
FileOutputFormat.setOutputPath(job, new Path("output"));
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}
但我发现了一些错误 import org.apache.hadoop.mapreduce
无法解析“我已经添加了hadoop jar文件”http://www.java2s.com/code/jar/h/downloadhadoop0210eclipsepluginjar.htm" .
hadoop版本hadoop 2.0.0-cdh4.2.0
EclipseJuno服务版本2能否有任何一个请帮助我解决这个问题。
2条答案
按热度按时间s5a0g9ez1#
你没有适当的依赖关系。实际上,您有一个用于hadoop开发的eclipse插件,它与hadoop的jar完全不同。
看看hadoop-0.21.0-eclipse-plugin.jar的内容,有没有看到hadoop核心类?
检查hadoop发行版并将真正的hadoop依赖项添加到构建工具(maven、ant、gradle…)。
如果您使用的是maven:
daupos2t2#
尝试包含以下使用hadoop下载的外部JAR:
$hadoop\u home/share/hadoop/mapreduce/hadoop-mapreduce-client-core-2.2.0.jar
$hadoop\u home/share/hadoop/mapreduce/hadoop-mapreduce-client-common-2.2.0.jar
$hadoop\u home/share/hadoop/common/hadoop-common-2.2.0.jar