我正试图在java的MapReduce2.x中执行mapreduce字数示例。。。。我已经创建了jar，但是在执行它的时候显示了一个错误，比如wordmapper类在我的包中找不到，但是我已经声明在我的包中…..请帮助我解决这个问题。。。。。。
这是我的wordcount驱动程序代码：

package com.mapreduce2.x;
public class WordCount {
public static void main(String args[]) throws IOException, ClassNotFoundException, InterruptedException
{
    Configuration conf=new Configuration();
    org.apache.hadoop.mapreduce.Job job= new org.apache.hadoop.mapreduce.Job(conf, "Word_Count");
    job.setMapperClass(WordMapper.class);
    job.setReducerClass(WordReducer.class);
    job.setMapOutputKeyClass(Text.class);
    job.setMapOutputValueClass(IntWritable.class);
    job.setOutputKeyClass(Text.class);
    job.setOutputValueClass(IntWritable.class);
    org.apache.hadoop.mapreduce.lib.input.FileInputFormat.setInputPaths(job, new Path(args[0]));
    org.apache.hadoop.mapreduce.lib.output.FileOutputFormat.setOutputPath(job, new Path(args[1]));
    job.waitForCompletion(true);
}}

这是我的wordmapper类：

public class WordMapper extends Mapper<LongWritable, Text, Text,IntWritable>{
private final static IntWritable one=new IntWritable(1);
private Text word=new Text();
public void map(LongWritable key, Text value, org.apache.hadoop.mapreduce.Reducer.Context context) throws IOException, InterruptedException
{
    String line=value.toString();
    StringTokenizer tokenizer=new StringTokenizer(line);
    while(tokenizer.hasMoreTokens())
    {
        word.set(tokenizer.nextToken());
        context.write(word, one);
    }
}}

减词器代码-

public class WordReducer extends Reducer<Text, IntWritable, Text, IntWritable>{
public void reduce(Text key, Iterator<IntWritable> values,Context context) throws IOException, InterruptedException
{
    int sum =0;
    while(values.hasNext())
    {
        sum= sum+values.next().get();
    }
    context.write(key, new IntWritable(sum));
}}

它在执行时显示以下错误-

15/05/29 10:12:26 INFO mapreduce.Job:  map 0% reduce 0%
15/05/29 10:12:33 INFO mapreduce.Job: Task Id : attempt_1432876892622_0005_m_000000_0, Status : FAILED
Error: java.lang.RuntimeException: java.lang.ClassNotFoundException: Class com.mapreduce2.x.WordMapper not found
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:2076)
    at org.apache.hadoop.mapreduce.task.JobContextImpl.getMapperClass(JobContextImpl.java:186)
    at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:742)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:341)
    at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:163)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:415)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1628)
    at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158)
Caused by: java.lang.ClassNotFoundException: Class com.mapreduce2.x.WordMapper not found
    at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:1982)
    at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:2074)
    ... 8 more