执行命令时
hadoop jar /home/edureka/Desktop/invertedindex.jar hdfs:/hdfs/inverted hdfs:/hdfs/invertedout
我得到下面的错误
有人能帮我修改代码吗
线程“main”java.lang.classnotfoundexception中出现异常:hdfs:.hdfs.inverted at java.net.urlclassloader$1.run(urlclassloader。java:366)在java.net.urlclassloader$1.run(urlclassloader。java:355)位于java.net.urlclassloader.findclass(urlclassloader)的java.security.accesscontroller.doprivileged(本机方法)。java:354)在java.lang.classloader.loadclass(类加载器。java:425)在java.lang.classloader.loadclass(classloader。java:358)在java.lang.class.forname0(本机方法)在java.lang.class.forname(类。java:270)在org.apache.hadoop.util.runjar.main(runjar。java:205)
我尝试了所有的先决条件,但仍然面临这个问题。 enter code here
代码如下:
import java.io.IOException;
import java.util.HashMap;
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.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.mapreduce.Reducer;
public class InvertedIndex {
public static class Map extends Mapper<LongWritable,Text,Text,Text> {
@Override
public void map(LongWritable key, Text value, Context context)
throws IOException,InterruptedException
{
String fileName = ((FileSplit) context.getInputSplit()).getPath().getName();
String line=value.toString();
String words[]=line.split(" ");
for(String s:words){
context.write(new Text(s), new Text(fileName));
}
}
}
public static class Reduce extends
Reducer<Text, Text, Text, Text> {
@Override
public void reduce(Text key, Iterable<Text> values, Context context)
throws IOException, InterruptedException {
HashMap m=new HashMap();
int count=0;
for(Text t:values){
String str=t.toString();
if(m!=null &&m.get(str)!=null){
count=(int)m.get(str);
m.put(str, ++count);
}else{`enter code here`
m.put(str, 1);
}
}
context.write(key, new Text(m.toString()));
}
}
public static void main(String[] args) throws Exception {
Configuration conf= new Configuration();
Job job = new Job(conf,"UseCase1");
//Defining the output value class for the mapper
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(Text.class);
job.setJarByClass(InvertedIndex.class);
job.setMapperClass(Map.class);
job.setReducerClass(Reduce.class);
//Defining the output value class for the mapper
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(Text.class);
job.setInputFormatClass(TextInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);
Path outputPath = new Path(args[1]);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, outputPath);
//deleting the output path automatically from hdfs so that we don't have delete it explicitly
outputPath.getFileSystem(conf).delete(outputPath);
//exiting the job only if the flag value becomes false
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}
2条答案
按热度按时间zbsbpyhn1#
您需要在hadoopjar命令中传递main类,如文档中所述。
你的命令
hadoop jar/home/edureka/desktop/invertedindex.jar hdfs:/hdfs/inverted hdfs:/hdfs/invertedout
应该是
hadoop jar/home/edureka/desktop/invertedindex.jar invertedindex hdfs:/hdfs/inverted hdfs:/hdfs/invertedout
也
job.setjarbyclass(invertedindex.class);
应该是
job.setjarbyclass(invertedindex);
相反。
我刚才也有过类似的讨论。
kpbpu0082#
hadoop命令应该知道在jar参数之后要执行哪个类:
Usage: hadoop jar <jar> [mainClass] args...
-参见手册所以您应该运行jar作为:
作业配置看起来不错。不要更改
job.setJarbyClass
:见班级作业