我正在写一个关于hadoop的项目。我有一个 1d 字符串数组，它的名字是"单词"。我
想将其发送到减速器，但我收到此错误：
Exception in thread "main" java.lang.NoSuchMethodError:org.apache.hadoop.mapred .InputSplit.write(Ljava/io/DataOutput;)V
我该怎么办？
谁能帮我？
这是我的映射器：
public abstract class Mapn implements Mapper<LongWritable, Text, Text, Text>{
@SuppressWarnings("unchecked")
public void map(LongWritable key, Text value, Context con) throws IOException, InterruptedException
{
String line = value.toString();
String[] words=line.split(",");
for(String word: words )
{
Text outputKey = new Text(word.toUpperCase().trim());
con.write(outputKey, words);
}
}
}
当我学习hadoop mapreduce工具时，除了传统的WordCount程序之外，我编写了自己的程序，然后为此导出了jar。现在，我正在共享我为之编写的程序hadoop-1.2.1 jar 依赖项。它用于转换数字并用单词写下这些数字，这是在 4 个 lacs 数字上处理的，没有任何错误。
所以这是程序：
package com.whodesire.count;
import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
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.hadoop.util.GenericOptionsParser;
import com.whodesire.numstats.AmtInWords;
public class CountInWords {
public static class NumberTokenizerMapper
extends Mapper <Object, Text, LongWritable, Text> {
private static final Text theOne = new Text("1");
private LongWritable longWord = new LongWritable();
public void map(Object key, Text value, Context context) {
try{
StringTokenizer itr = new StringTokenizer(value.toString());
while (itr.hasMoreTokens()) {
longWord.set(Long.parseLong(itr.nextToken()));
context.write(longWord, theOne);
}
}catch(ClassCastException cce){
System.out.println("ClassCastException raiseddd...");
System.exit(0);
}catch(IOException | InterruptedException ioe){
ioe.printStackTrace();
System.out.println("IOException | InterruptedException raiseddd...");
System.exit(0);
}
}
}
public static class ModeReducerCumInWordsCounter
extends Reducer <LongWritable, Text, LongWritable, Text>{
private Text result = new Text();
//This is the user defined reducer function which is invoked for each unique key
public void reduce(LongWritable key, Iterable<Text> values,
Context context) throws IOException, InterruptedException {
/*** Putting the key, which is a LongWritable value,
putting in AmtInWords constructor as String***/
AmtInWords aiw = new AmtInWords(key.toString());
result.set(aiw.getInWords());
//Finally the word and counting is sent to Hadoop MR and thus to target
context.write(key, result);
}
}
public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
/****
*** all random numbers generated inside input files has been
*** generated using url https://andrew.hedges.name/experiments/random/
****/
//Load the configuration files and add them to the the conf object
Configuration conf = new Configuration();
String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
Job job = new Job(conf, "CountInWords");
//Specify the jar which contains the required classes for the job to run.
job.setJarByClass(CountInWords.class);
job.setMapperClass(NumberTokenizerMapper.class);
job.setCombinerClass(ModeReducerCumInWordsCounter.class);
job.setReducerClass(ModeReducerCumInWordsCounter.class);
//Set the output key and the value class for the entire job
job.setMapOutputKeyClass(LongWritable.class);
job.setMapOutputValueClass(Text.class);
//Set the Input (format and location) and similarly for the output also
FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
//Setting the Results to Single Target File
job.setNumReduceTasks(1);
//Submit the job and wait for it to complete
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}
我建议你查看你添加的Hadoopjars，特别是在hadoop-core-x.x.x.jar上，因为在看到你的错误之后，你似乎没有在项目中添加一些mapreducejar。