Mapreduce 在oozie作业中获取错误
我有一个WordCount MapReduce作业,当它从hadoop cli运行时,它运行良好并提供了输出。但是当我通过oozie运行作业时,它抛出了一个错误'error:java.io.IOException:map中key的类型不匹配:expected org.apache.hadoop.io.Text,received org.apache.hadoop.io.LongWritable' 这是密码Mapreduce 在oozie作业中获取错误,mapreduce,oozie,Mapreduce,Oozie,我有一个WordCount MapReduce作业,当它从hadoop cli运行时,它运行良好并提供了输出。但是当我通过oozie运行作业时,它抛出了一个错误'error:java.io.IOException:map中key的类型不匹配:expected org.apache.hadoop.io.Text,received org.apache.hadoop.io.LongWritable' 这是密码 package Drivers; import java.io.IOException;
package Drivers;
import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
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.Tool;
import org.apache.hadoop.util.ToolRunner;
public class WordCount extends Configured implements Tool
{
public static void main(String[] args) throws Exception
{
int res = ToolRunner.run(new Configuration(), new WordCount(), args);
System.exit(res);
}
@Override
public int run(String[] args) throws Exception
{
Job job = Job.getInstance(getConf(), "Tool Job");
job.setJarByClass(WordCount.class);
job.setMapperClass(WordMap.class);
job.setReducerClass(RedForSum.class);
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(IntWritable.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
return job.waitForCompletion(true) ? 0 : 1;
}
//map method
public static class WordMap extends Mapper<LongWritable,Text,Text,IntWritable>
{
public void map(LongWritable k, Text v,Context con) throws IOException, InterruptedException
{
String line=v.toString();
StringTokenizer t = new StringTokenizer(line);
while(t.hasMoreTokens())
{
String word=t.nextToken();
con.write(new Text(word),new IntWritable(1));
}
}
}
//reducer method
public static class RedForSum extends Reducer<Text, IntWritable,Text,IntWritable>
{
public void reduce(Text k, Iterable<IntWritable> vlist, Context con) throws IOException, InterruptedException
{
int tot=0;
for(IntWritable v:vlist)
tot+=v.get();
con.write(k, new IntWritable(tot));
}
}
}
这是我的错误
错误:java.io.IOException:映射中的键类型不匹配:预期为org.apache.hadoop.io.Text,收到org.apache.hadoop.io.LongWritable
位于org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:1072)
位于org.apache.hadoop.mapred.MapTask$NewOutputCollector.write(MapTask.java:715)
位于org.apache.hadoop.mapreduce.task.taskInputOutContextImpl.write(taskInputOutContextImpl.java:89)
位于org.apache.hadoop.mapreduce.lib.map.WrappedMapper$Context.write(WrappedMapper.java:112)
位于org.apache.hadoop.mapreduce.Mapper.map(Mapper.java:124)
位于org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:145)
位于org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:787)
位于org.apache.hadoop.mapred.MapTask.run(MapTask.java:341)
位于org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:163)
位于java.security.AccessController.doPrivileged(本机方法)
位于javax.security.auth.Subject.doAs(Subject.java:415)
位于org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1671)
位于org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158)
有人能告诉我哪里错了吗
提前感谢。问题似乎出在工作流xml中。这里的属性名称应该是
mapreduce.map.class
和mapreduce.reduce.class
,而不是mapreduce.mapper.class
和mapreduce.reducer.class
。因此,修改后的工作流应该具有这些属性
<property>
<name>mapreduce.map.class</name>
<value>Drivers.WordCount$WordMap</value>
</property>
<property>
<name>mapreduce.reduce.class</name>
<value>Drivers.WordCount$RedForSum</value>
</property>
mapreduce.map.class
Drivers.WordCount$WordMap
mapreduce.reduce.class
Drivers.WordCount$RedForSum
有关这方面的更多信息,请参考如果我更改xml
错误,我将收到以下错误:java.lang.RuntimeException:java.lang.ClassNotFoundException:Class Drivers.WordCount$WordMap未找到
@Ashok应该是Drivers.WordCount.WordMap
和Drivers.WordCount.RedForSum
。试试这些值。@Raju Sharma,你说得对。但只有在我将mapred.mapoutput.key.class
和mapred.mapoutput.value.class
标记添加到工作流中时,作业才成功完成mapred.mapoutput.key.class org.apache.hadoop.io.Text mapred.mapoutput.value.class org.apache.hadoop.io.intwriteable
oozie job -oozie http://localhost:11000/oozie -config /home/cloudera/job.properties -run
<property>
<name>mapreduce.map.class</name>
<value>Drivers.WordCount$WordMap</value>
</property>
<property>
<name>mapreduce.reduce.class</name>
<value>Drivers.WordCount$RedForSum</value>
</property>