Question

我使用Mahout

创建了以下Mapper和Reducer

package mypackage.ItemSimilarity;

import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.mahout.math.VarLongWritable;

public class ItemPrefMapper extends
        Mapper<LongWritable, Text, VarLongWritable, VarLongWritable> {

    private static final Pattern NUMBERS = Pattern.compile("(\\d+)");

    @Override
    public void map(LongWritable key, Text value, Context context)
            throws IOException, InterruptedException {
        String line = value.toString();
        Matcher m = NUMBERS.matcher(line);
        m.find();
        VarLongWritable userID = new VarLongWritable(Long.parseLong(m.group()));
        VarLongWritable itemID = new VarLongWritable();
        while (m.find()) {
            itemID.set(Long.parseLong(m.group()));
            context.write(userID, itemID);
        }
    }
}

减少课程

package mypackage.ItemSimilarity;

import java.io.IOException;

import org.apache.hadoop.mapreduce.Reducer;
import org.apache.mahout.math.RandomAccessSparseVector;
import org.apache.mahout.math.VarLongWritable;
import org.apache.mahout.math.Vector;
import org.apache.mahout.math.VectorWritable;

public class UserVectorReducer
        extends
        Reducer<VarLongWritable, VarLongWritable, VarLongWritable, VectorWritable> {
    @Override
    public void reduce(VarLongWritable userID,
            Iterable<VarLongWritable> itemPrefs, Context context)
            throws IOException, InterruptedException {
        Vector userVector = new RandomAccessSparseVector(Integer.MAX_VALUE, 100);
        for (VarLongWritable itemPref : itemPrefs) {
            userVector.set((int) itemPref.get(), 1.0f);
        }
        context.write(userID, new VectorWritable(userVector));
    }

}

运行此配置的Spring配置

<job id="mahoutJob" input-path="/home/ubuntu/input/data.txt" output-path="/home/ubuntu/output"
mapper="mypackage.ItemSimilarity.ItemPrefMapper" 
reducer="mypackage.ItemSimilarity.UserVectorReducer" 
jar-by-class="mypackage.ItemSimilarity.ItemPrefMapper"/>

<job-runner id="myjob-runner" pre-action="setupScript"  job-ref="mahoutJob" 
run-at-startup="true"/>

当我运行时，我收到以下错误。我扩展了Hadoop映射器类，但Spring表示它不是映射器类。

java.lang.RuntimeException：class mypackage.ItemSimilarity.ItemPrefMapper not org.apache.hadoop.mapreduce.Mapper 在org.apache.hadoop.conf.Configuration.setClass（Configuration.java:931）在org.apache.hadoop.mapreduce.Job.setMapperClass（Job.java:175）在org.springframework.data.hadoop.mapreduce.JobFactoryBean.afterPropertiesSet（JobFactoryBean.java:153）在org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods（AbstractAutowireCapableBeanFactory.java:1571）在org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean（AbstractAutowireCapableBeanFactory.java:1509）在org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean（AbstractAutowireCapableBeanFactory.java:521）在org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean（AbstractAutowireCapableBeanFactory.java:458）

Answer 1

您确定 jar-by-class 元素吗？因为它应该指向您实例化ApplicationContext实例的main方法。

另外，您确定您的包裹名称吗？

com.threepillar.labs.ItemSimilarity.ItemPrefMapper

和

mypackage.ItemSimilarity.ItemPrefMapper

在Spring-data hadoop上运行作业的问题

1 个答案: