运行wordcount程序的修改版本时出错(添加了Map器逻辑以将符号从单词中分离出来)。
错误:java.lang.runtimeexception:java.lang.classnotfoundexception:class wcount.wordcount$tokenizermapper
os:hortonworks沙盒托管2.6 hadoop版本我就是这么做的-
修改wordcount.java以引入Map器逻辑
使用命令编译wordcount.java javac -classpath /home/test_user/jars/commons-cli-1.2.jar:/home/test_user/jars/hadoop-common-2.6.0.2.2.0.0-2041.jar:/home/test_user/jars/hadoop-mapreduce-client-core-2.6.0.2.2.0.0-2041.jar -d /home/test_user/hadoopjar/wordcountclass -Xlint:deprecation WordCount.java
使用创建wordcount.jar jar cvf wordcount.jar wcount
(其中wcount是包含所有3个类(wordcount、tokenizer和intsumreducer)的文件夹)。下面是jar文件的样子 wcount wcount/WordCount.class wcount/WordCount$TokenizerMapper.class wcount/WordCount$intsumreducer.class
使用命令- hadoop jar wordcount.jar WordCount /home/user/test_user/wordcount/wordcount.txt /home/user/test_user/wordcount/out8
它在尝试运行Map作业后出错 Error: java.lang.RuntimeException: java.lang.ClassNotFoundException: Class wcount.WordCount$TokenizerMapper
代码是
package wcount;
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.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.hadoop.util.GenericOptionsParser;
public class WordCount {
public static class TokenizerMapper
extends Mapper<Object, Text, Text, IntWritable>{
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(Object key, Text value, Context context
) throws IOException, InterruptedException {
StringTokenizer itr = new StringTokenizer(value.toString());
char[] chararray = {'(' , ')' , ';' , ':' , '.' , '/' , '{' , '}' , ']' , ']'};
String temp;
while (itr.hasMoreTokens())
{
temp = itr.nextToken();
for (short i = 0; i < chararray.length; i++)
{
if (temp.charAt(0) == chararray[i])
{
temp = temp.substring(1);
}
if (temp.charAt(temp.length() - 1) == chararray[i])
{
temp = temp.substring(0, temp.length() - 1);
}
}
word.set(temp);
context.write(word, one);
}
}
}
public static class IntSumReducer
extends Reducer<Text,IntWritable,Text,IntWritable> {
private IntWritable result = new IntWritable();
public 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();
String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
if (otherArgs.length < 2) {
System.err.println("Usage: wordcount <in> [<in>...] <out>");
System.exit(2);
}
Job job = new Job(conf, "word count");
job.setJarByClass(WordCount.class);
job.setMapperClass(TokenizerMapper.class);
job.setCombinerClass(IntSumReducer.class);
job.setReducerClass(IntSumReducer.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
for (int i = 0; i < otherArgs.length - 1; ++i) {
FileInputFormat.addInputPath(job, new Path(otherArgs[i]));
}
FileOutputFormat.setOutputPath(job,
new Path(otherArgs[otherArgs.length - 1]));
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}
1条答案
按热度按时间sg2wtvxw1#
您没有在作业设置中设置任何inputformatter,因此默认情况下,您的输入格式化程序是textinputformatter。所以这项工作可能需要一个
LongWritable
相对于普通的Object
. 你能换一下房间吗extends Mapper<Object
至extends Mapper<LongWritable
还有map(Object key
至map(LongWritable key
?