Scala: parse JSON file into List[DBObject] - json

Question

1.Input is JSON file that contains multiple records. Example:
[
{"user": "user1", "page": 1, "field": "some"},
{"user": "user2", "page": 2, "field": "some2"},
...
]
2.I need to load each record from the file as a Document to MongoDB collection.
Using casbah for interacting with mongo, inserting data may look like:
def saveCollection(inputListOfDbObjects: List[DBObject]) = {
val xs = inputListOfDbObjects
xs foreach (obj => {
Collection.save(obj)
})
Question: What is the correct way (using scala) to parse JSON to get data as List[DBObject] at output?
Any help is appreciated.

Answer 1

You could use the parser combinator library in Scala.
Here's some code I found that does this for JSON: http://booksites.artima.com/programming_in_scala_2ed/examples/html/ch33.html#sec4
Step 1. Create a class named JSON that contains your parser rules:
import scala.util.parsing.combinator._
class JSON extends JavaTokenParsers {
def value : Parser[Any] = obj | arr |
stringLiteral |
floatingPointNumber |
"null" | "true" | "false"
def obj : Parser[Any] = "{"~repsep(member, ",")~"}"
def arr : Parser[Any] = "["~repsep(value, ",")~"]"
def member: Parser[Any] = stringLiteral~":"~value
}
Step 2. In your main function, read in your JSON file, passing the contents of the file to your parser.
import java.io.FileReader
object ParseJSON extends JSON {
def main(args: Array[String]) {
val reader = new FileReader(args(0))
println(parseAll(value, reader))
}
}