If you’ve been wondering whether storing files in Hadoop HDFS programmatically is difficult, I have good news – it’s not.

For the purpose of this example i’ll be using my favorite (recently) language – Scala.

Here’s what you need to do:

1. Start a new SBT project in IntelliJ
2. Add the “hadoop-client” dependency (Important: You must use the same version of the client, as is the version of the Hadoop server you’ll be writing files to)

   libraryDependencies ++= Seq(
     "org.apache.hadoop" % "hadoop-client" % "2.7.0"
   )
   

3. Check in Hadoop configuration the value of “fs.default.name” property (/etc/hadoop/core-site.xml). This will be the URI you need in order to point the app code at your Hadoop Cluster
4. Write few lines of code

   import org.apache.hadoop.conf.Configuration
   import org.apache.hadoop.fs.{FileSystem, Path}
   
   object Hdfs extends App {
   
     def write(uri: String, filePath: String, data: Array[Byte]) = {
       System.setProperty("HADOOP_USER_NAME", "Mariusz")
       val path = new Path(filePath)
       val conf = new Configuration()
       conf.set("fs.defaultFS", uri)
       val fs = FileSystem.get(conf)
       val os = fs.create(path)
       os.write(data)
       fs.close()
     }
   }
   

5. Use the code written above

     Hdfs.write("hdfs://0.0.0.0:19000", "test.txt", "Hello World".getBytes)
   

That’s all there is to it, really

Cheers 🙂

Tagged: Hadoop, Scala