Cloudera MapReduce计数器getValue错误

我目前正在使用Cloudera上的计数器开发MapReduce map only程序。Mapper类将递增一个特定计数器,我想在MapReduce作业完成后显示每个计数器的最终值。下面是我的映射器类代码:

public class MyMapper extends Mapper<LongWritable, Text, Text, IntWritable> {
    public static enum MY_COUNTER {
        C1,
        C2
    }

    //mapper logic that produces String variable 'final'

    if (final.equals("Foo")) context.getCounter(MY_COUNTER.C1).increment(1);
    else context.getCounter(MY_COUNTER.C2).increment(1);

    //context.write() method
}

下面是我的驾驶员等级代码:

public class MyDriver extends Configured implements Tool {
    public static void main(String[] args) throws Exception {
        int exitCode = ToolRunner.run(new MyDriver(), args);
        System.exit(exitCode);
    }

    public int run(String[] args) throws Exception {
        Job job = Job.getInstance(getConf(), "My MapReduce");

        //Job configuration:
        //Sets mapper to MyMapper class
        //Sets num of Reduce tasks to 0
        //Other necessary job config

        boolean success = job.waitForCompletion(true);
        if (success) {
            Counter counter1 = job.getCounters().findCounter("MY_COUNTER", "C1");
            System.out.println(counter1.getDisplayName() + ": " + counter1.getValue());
            Counter counter2 = job.getCounters().findCounter("MY_COUNTER", "C2");
            System.out.println(counter2.getDisplayName() + ": " + counter2.getValue());
            return 0;
        }
        else return 1;
    }
}

运行jar文件时,作业成功执行。因为我设置了 job.waitForCompletion() 参数为true时,它会将所有MapReduce进度打印到终端。我可以从那里看到我的计数器的值。

18/03/27 09:59:58 INFO mapreduceJob: Counters: 35

    //all built-in counters

    MyMapper$MY_COUNTER
        C1=837
        C2=119

但是,当我在作业完成后打印计数器的值时(从 if(success) 作为MyDriver类的一部分),打印的值都是零。

C1: 0
C2: 0

有没有关于我可能错在哪里的建议?

注意:我使用的是Hadoop 2.6.0-cdh5.12.0