我有一个简单的mapreduce工作，我从avro网站借了一些小修改（我删除了reducer）。它基本上需要一个简单的avro文件作为输入。以下是avro文件的模式
avro架构：

{
"type": "record",
"name": "User",
"fields": [
{"name": "name", "type": "string"},
{"name": "favorite_number",  "type": "int"},
{"name":"favorite_color", "type": "string"}
]
}

以下是我的mapreduce工作（Map器和主要功能）：

public class ColorCountMapper extends Mapper<AvroKey<User>, NullWritable, Text, IntWritable> {

@Override
public void map(AvroKey<User> key, NullWritable value, Context context)  throws IOException, InterruptedException {

  CharSequence color = key.datum().getFavoriteColor();
  if (color == null) {
    color = "none";
  }
  context.write(new Text(color.toString()), new IntWritable(1));
}

}
和

public static void main(String[] args) throws Exception {

    Configuration conf = new Configuration();
    Job job = Job.getInstance(conf, "TestColor");
    job.setJarByClass(runClass.class);
    job.setJobName("Color Count");

    FileInputFormat.setInputPaths(job, new Path("in"));
    FileOutputFormat.setOutputPath(job, new Path("out"));

    job.setInputFormatClass(AvroKeyInputFormat.class);
    job.setMapperClass(ColorCountMapper.class);
    AvroJob.setInputKeySchema(job, User.getClassSchema());
    job.setMapOutputKeyClass(Text.class);
    job.setMapOutputValueClass(IntWritable.class);

    boolean r = job.waitForCompletion(true);
    System.out.println(r);  
}

当我运行程序时，它返回false并且没有成功。我搞不懂这个问题。有人能帮忙吗？