Skip to main content

CSV Parsing with Scala

Good new about Scala is, actually not only about Scala but all other JVM based languages is that they can take advantages of Java libraries. Since the Scala is a JVM based programming language its easy to use Java libraries and classes with it.

I needed to parse complex CSV file with Scala and create MongoDB object to represent an each row of the CSV file. This would have been easy if I was asked to create MongoDB objects using a JSON file because the JSON is highly supported by the MongoDB. But here I only got complex CSV file with loads of data. First I found some good tutorial about Scala CSV parsing and started my work.

Yes I'm using Play framework 2.0.2 with Scala and MongoDB. I found opencsv is the best solution for parsing CSV files with Scala. Opencsv is for Java but as we already know that Scala is a JVM based language we can go with it.

First I updated my build configuration file to reflect the application dependencies for opencsv.

add this dependencies to your config file.
"net.sf.opencsv" % "opencsv" % "2.1"
This will download the dependent jar files to your repository. You should close eclipse and compile the project and you can see that dependencies are downloaded.

Comments

Popular posts from this blog

Upload CSV file using opencsv with Play 2.0.2, Scala and MongoDB

Hi Everyone... Today I'm going to explain you that how we could upload a CSV file with list of products to the MongoDB table. The way I'm describing here might me inefficient but still it is useful. We know that Scala is running on JVM and so that we can use any java library with Scala . I will use OpenCSV as a CSV parser for this program. OpenCSV is a CSV parser library for Java. No matter it is for java here we will use it with Scala. First we should have MongoDB up and running. Include following opencsv dependency in your build file. I'm using SBT as building tool. "net.sf.opencsv" % "opencsv" % "2.1" Here next I will create view file. Name of this file will be 'index.scala.html'. @(message: String)(implicit request: RequestHeader, flash:Flash, l: Lang=Lang("en")) @import play.api.i18n._ @import views.html.helper._ @main(message, null) { //print messages @if(flash.data.contains("message")){ ...

Scala : not enough arguments for constructor : ()

not enough arguments for constructor : ( ) Here Im trying to create new Object from case class in scala, but I get this error withing my following code. def getTax(id: ObjectId): models.Tax = { models.Tax.findOne(MongoDBObject("_id" -> id)) .getOrElse(new models.Tax) // this line is generating error } It says that it cannot build a new Tax object without providing the constructor arguments. That is correct, If we want to buld an object we should provide constructor arguments. Just take a look at my Tax class. case class Tax( id: ObjectId = new ObjectId, var name: String, var description: String, var defaultFlag: Boolean, var rate: List[Rate] = List.empty ){ } I have specified default values for id field and rate field but what about name, description and defaultFlag field. There are no default values for them. So if we want to create and object like this 'new models.Tax' (which means without passing arguments to constructor), you should pr...

Way to Resolve 'no persistent classes found for query class'

Last few days I had experience about this issue. I was developing test application with Spring 3, Hibernate 3.3.1, Maven 3 and Jboss 5.0. I had a class called Employer and it was annotated. Here I have given sample. This is under the package hrm.com.domain. @Entity @Table(name="employer") public class Employer { @Id @Column(name="ID") @GeneratedValue private Integer id; My application was Spring MVC application and Im not going to post all the source code here. I had following configuration files. 1. hibernate.cfg.xml 2. spring-servlet.xml 3. web.xml Here is javax.persistence dependency in my POM.xml file. (I have only post here is important part) javax.persistence persistence-api 1.0 Then I built the application and copy the war file into jboss_home/server/default/deploy directory. Then Server is started. Server is started without any issue. Interested thing happened when I run the application in the web browser. Application needs to list down all the employ...