我已经运行了 map/reduce 作业，但它不起作用。我该如何解决这个错误？？你能告诉PLZ吗？
13/09/16 15:58:47 INFO mapred.JobClient: Task Id : attempt_201307081931_0006_m_000000_2, Status : FAILED
java.lang.ClassCastException: class com.sun.jersey.core.impl.provider.entity.XMLJAXBElementProvider$Text
at java.lang.Class.asSubclass(Class.java:3116)
at org.apache.hadoop.mapred.JobConf.getOutputKeyComparator(JobConf.java:774)
at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>(MapTask.java:959)
at org.apache.hadoop.mapred.MapTask$NewOutputCollector.<init>(MapTask.java:674)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:756)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
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:1149)
at org.apache.hadoop.mapred.Child.main(Child.java:249)
我的源代码：
WordCountMapper.java
public class WordCountMapper extends Mapper<LongWritable, Text, Text, IntWritable> {
private final static IntWritable one = new IntWritable();
private Text word = new Text();
public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException{
StringTokenizer itr = new StringTokenizer(value.toString());
while(itr.hasMoreTokens()) {
word.set(itr.nextToken());
context.write(word, one);
}
}
}
WordCountReducer.java
public class WordCountReducer extends Reducer<Text, IntWritable, Text, IntWritable> {
private IntWritable result = new IntWritable();
public void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException{
int sum = 0;
for(IntWritable val : values){
sum += val.get();
}
result.set(sum);
context.write(key, result);
}
}
WordCount.java
public class WordCount {
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
if(args.length != 2){
System.err.println("Usage: WordCount <input> <output>");
System.exit(2);
}
Job job = new Job(conf, "wordCount");
job.setJarByClass(WordCount.class);
job.setMapperClass(WordCountMapper.class);
job.setReducerClass(WordCountReducer.class);
job.setInputFormatClass(TextInputFormat.class);
job.setOutputFormatClass(TextOutputFormat.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FileInputFormat.addInputPath(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
job.waitForCompletion(true);
}
}