How to convert an Int to a String of a given length with leading zeros to align?

Question

How can I convert an Int to a 7-character long String, so that 123 is turned into \"0000123\"?

Answer 1

In case this Q&A becomes the canonical compendium,

scala> import java.text._
import java.text._

scala> NumberFormat.getIntegerInstance.asInstanceOf[DecimalFormat]
res0: java.text.DecimalFormat = java.text.DecimalFormat@674dc

scala> .applyPattern("0000000")

scala> res0.format(123)
res2: String = 0000123