如何在Hadoop-20 api中指定KeyValueTextInputFormat分隔符? [英] How to specify KeyValueTextInputFormat Separator in Hadoop-.20 api?
问题描述
在新的API(apache.hadoop.mapreduce.KeyValueTextInputFormat)中,如何指定分隔符(分隔符)而不是tab(默认值)来分隔键和值。
样本输入:
one,first line
two,second line
需要输出:
键:一个
值:第一行
键:两个
值:第二行
我将KeyValueTextInputFormat指定为:
Job job = new Job(conf,Sample);
job.setInputFormatClass(KeyValueTextInputFormat.class);
KeyValueTextInputFormat.addInputPath(job,new Path(/ home / input.txt));
这对于标签作为分隔符来说工作得很好。
在较新的API中,您应该使用 mapreduce.input.keyvaluelinerecordreader.key.value.separator
配置属性。以下是一个例子:
Configuration conf = new Configuration();
conf.set(mapreduce.input.keyvaluelinerecordreader.key.value.separator,,);
工作职位=新职位(conf);
job.setInputFormatClass(KeyValueTextInputFormat.class);
//下一个工作设置
In new API (apache.hadoop.mapreduce.KeyValueTextInputFormat) , how to specify separator (delimiter) other than tab(which is default) to separate key and Value.
Sample Input :
one,first line
two,second line
Ouput Required :
Key : one
Value : first line
Key : two
Value : second line
I am specifying KeyValueTextInputFormat as :
Job job = new Job(conf, "Sample");
job.setInputFormatClass(KeyValueTextInputFormat.class);
KeyValueTextInputFormat.addInputPath(job, new Path("/home/input.txt"));
This is working fine for tab as a separator.
In the newer API you should use mapreduce.input.keyvaluelinerecordreader.key.value.separator
configuration property.
Here's an example:
Configuration conf = new Configuration();
conf.set("mapreduce.input.keyvaluelinerecordreader.key.value.separator", ",");
Job job = new Job(conf);
job.setInputFormatClass(KeyValueTextInputFormat.class);
// next job set-up
这篇关于如何在Hadoop-20 api中指定KeyValueTextInputFormat分隔符?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!