如何通过 API 访问 Hadoop 计数器值?
在 Hadoop 中，我们可以在 map/reduce 任务中增加计数器，如下所示:
In Hadoop we can increment counter in map/reduce task, it looks like this:
...
context.getCounter(MyCountersEnum.SomeCounter).increment(1);
...
你可以在日志中找到它们的值.
Than you can find their value in log.
作业完成后如何从代码中访问它们?
How do you access them from code after job completes?
什么是读取计数器值的 Hadoop API?
What is Hadoop API to read counter value?
推荐答案
我刚刚找到了答案 这里.
您需要一个作业对象来访问计数器:
You need a job object to access the counters:
Counters counters = job.getCounters();
Counter counter = counters.findCounter(MyCountersEnum.SomeCounter);
System.out.println(counter.getDisplayName() + ": " + counter.getValue());
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