Menu
I've recently started working with Hadoop and have been learning how to write MapReduce jobs. All over the internet, I can find examples and tutorials for writing MapReduce jobs, but they all include import statements that go something like 'import org.apache.hadoop.util.*;'. I cannot find where to download any of those classes and I can't even begin writing jobs until I do find them. Where can I download the necessary plug-in?
I've tried the plug-in that comes along with a Hadoop download and I've also tried a MapReduce plug-in for Eclipse distributed by IBM, but neither has worked. Where can I download the correct one?
Thanks!
900
The reducer uses the right data types specific to Hadoop MapReduce (line 50-52). The reduce (Object, Iterable, Context) method is called for each <key, (collection of values)> in the sorted inputs. The output of the reduce task is written to a RecordWriter via TaskInputOutputContext. write(Object, Object) (line 54-56).
The partitioner is responsible for processing the map output. Once MapReduce splits the data into chunks and assigns them to map tasks, the framework partitions the key-value data. This process takes place before the final mapper task output is produced. MapReduce partitions and sorts the output based on the key.
I assume you're using java...
Here you can download it. http://hadoop.apache.org/common/releases.html#Download
If you're on 20.X, you'll just need to import (putting it into your classpath) the hadoop-0.20.X-core.jar in the "root" folder. If > 20.X you have to use three jars: hadoop-common-0.21.0.jar, hadoop-hdfs-0.21.0.jar, hadoop-mapred-0.21.0.
Obviously you have to replace the 'x' with the suffix of the version you're using.
90
You can use Maven repositories for that. I'm assuming you are using Java and Maven.
Repos are here: https://repository.cloudera.com/index.html
36
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
