输出值中可以有一个标志列。稍后您可以处理输出并按标志列将其拆分。

创建自定义o/p格式类，如下所示

package com.visa.util;

import java.io.IOException;

import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.OutputCommitter;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat;

public class CostomOutputFormat<K, V> extends SequenceFileOutputFormat<K, V>{

    @Override
    public void checkOutputSpecs(JobContext arg0) throws IOException {
    }

    @Override
    public OutputCommitter getOutputCommitter(TaskAttemptContext arg0) throws IOException {
        return super.getOutputCommitter(arg0);
    }

    @Override
    public RecordWriter<K, V> getRecordWriter(TaskAttemptContext arg0) throws IOException, InterruptedException {
        return super.getRecordWriter(arg0);
    }

}

并在驱动程序类中使用：

job.setOutputFormatClass(CostomOutputFormat.class);

它将跳过是否存在o/p目录的检查。