的Hadoop類未發現異常

Question

我工作的Hadoop的簡單的程序，我跟着這個教程的步驟： http://www.bogotobogo.com/Hadoop/BigData_hadoop_Creating_Java_Wordcount_Project_with_Eclipse_MapReduce2.php

即使我試圖在兩臺不同的機器，它一直顯示此異常：

Exception in thread "main" java.lang.ClassNotFoundException: test.java 
at java.net.URLClassLoader$1.run(URLClassLoader.java:366) 
at java.net.URLClassLoader$1.run(URLClassLoader.java:355) 
at java.security.AccessController.doPrivileged(Native Method) 
at java.net.URLClassLoader.findClass(URLClassLoader.java:354) 
at java.lang.ClassLoader.loadClass(ClassLoader.java:425) 
at java.lang.ClassLoader.loadClass(ClassLoader.java:358) 
at java.lang.Class.forName0(Native Method) 
at java.lang.Class.forName(Class.java:270) 
at org.apache.hadoop.util.RunJar.run(RunJar.java:214) 
at org.apache.hadoop.util.RunJar.main(RunJar.java:136) 

---

package pa2; 
import org.apache.hadoop.conf.Configured; 
import org.apache.hadoop.fs.Path; 
import org.apache.hadoop.io.IntWritable; 
import org.apache.hadoop.io.Text; 
import org.apache.hadoop.mapred.FileOutputFormat; 
import org.apache.hadoop.mapred.FileInputFormat; 
import org.apache.hadoop.mapred.JobClient; 
import org.apache.hadoop.mapred.JobConf; 
import org.apache.hadoop.util.Tool; 
import org.apache.hadoop.util.ToolRunner; 


public class test extends Configured implements Tool{ 


public int run(String[] args) throws Exception 
{ if (args.length<2) 
{ 
    System.out.println("plz give proper arguments"); 
    return -1; 
} 
     //creating a JobConf object and assigning a job name for identification purposes 
     JobConf conf = new JobConf(test.class); 

     FileInputFormat.setInputPaths(conf, new Path(args[0])); 
     FileOutputFormat.setOutputPath(conf, new Path(args[1])); 

     conf.setMapperClass(mapper.class); 

     conf.setMapOutputKeyClass(Text.class); 
     conf.setMapOutputValueClass(IntWritable.class); 

     conf.setOutputKeyClass(Text.class); 
     conf.setOutputValueClass(IntWritable.class); 

     JobClient.runJob(conf); 

     return 0; 
} 


public static void main(String[] args) throws Exception 
{ 
     // this main function will call run method defined above. 
    int exitcode = ToolRunner.run(new test(),args); 
     System.exit(exitcode); 
} 
} 

可以請你告訴我這裏有什麼問題？

更新：

映射類：

package pa2; 
import java.io.IOException; 
import org.apache.hadoop.io.IntWritable; 
import org.apache.hadoop.io.LongWritable; 
import org.apache.hadoop.io.Text; 
import org.apache.hadoop.mapred.MapReduceBase; 
import org.apache.hadoop.mapred.Mapper; 
import org.apache.hadoop.mapred.OutputCollector; 
import org.apache.hadoop.mapred.Reporter; 


public class mapper extends MapReduceBase 
     implements Mapper<LongWritable,Text, Text, IntWritable> 
{ 
      public void map(LongWritable Key, Text value, 
      OutputCollector<Text, IntWritable> output, Reporter r) 
      throws IOException { 


      int i=0; 
      String [] array = new String [50]; 


         String name; 
         String year; 
         String s=value.toString(); 

         for (String word:s.split(",")){ 

        word = s.substring(0, s.indexOf(",")+1); 
        year= word.substring(0, s.indexOf(",")+1); 
        name=word.substring(s.indexOf(",")+1); 
        int theyear= Integer.parseInt(year); 


        if(theyear<2000){ 
         array[i] =name; 
         output.collect(new Text(word), new IntWritable(1)); 

         i++;} 

        }  
    } 
} 

我沒有寫減速類。我將項目導出爲jar文件，並且我創建了一個名爲movies的文本文件作爲程序的輸入。然後在終端中寫道的：

[cloudera@quickstart ~]$ cd workspace 
[cloudera@quickstart workspace]$ ls 
pa2 pa2.jar training 
[cloudera@quickstart workspace]$ hadoop jar pa2.jar test movies.txt output.txt 
Exception in thread "main" java.lang.ClassNotFoundException: test 
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366) 
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354) 
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425) 
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358) 
    at java.lang.Class.forName0(Native Method) 
    at java.lang.Class.forName(Class.java:270) 
    at org.apache.hadoop.util.RunJar.run(RunJar.java:214) 
    at org.apache.hadoop.util.RunJar.main(RunJar.java:136) 

Answer 1

沒有保證，這是解決眼前的問題，但

package pa2; 

這是附加到的類名。換句話說，完全合格的類名是pa2.test。

所以，儘量

hadoop jar ~/workspace/pa2.jar pa2.test input output 

如果您使用的是默認包這樣的教程顯示，你就不需要在命令行上指定包。

Answer 2

應該在這裏提供

conf.setMapperClass(mapper.class); 

如果您嘗試使用默認的地圖類地圖類的實際名稱，然後寫上「Mapper.class」 。