We use fixedformat4j on my current project and I am developing fixedformat4j along the way. We have found the initial 1.0.0 release lacking in the ability to parse signed numbers like:

00011050+, that equals a two digit signed bigdecimal number 100.50

This is how you would annotate your method to be able to read and write a string like 000010050+:

...
@Field(offset = 1, length = 10, align = Align.RIGHT, paddingChar = '0')
@FixedFormatDecimal(useDecimalDelimiter = true)
@FixedFormatNumber(sign = Sign.APPEND)
public BigDecimal getBigDecimalData() {
  return bigDecimalData;
}
...

This was added in version 1.1.0, but some bugs was spotted and fixed so quickly a 1.1.1 version was released.

Feel free to download the latest version and take a look at the changelist.

At my current project we decided to use fixedformat4j.
So after all your feedback on my recent draft implementation I have been working quite hard this weekend to get fixedformat4j shined up.

The implementation looks pretty much what Niels proposed here and I implemented support for bigdecimal as Bob wished. That means that javassist is gone and fixedformat4j is now much less intrusive - you don’t have ti extend or implement anything to be able to load and export data.

You can see just how easy on the “getting started” at the frontpage of the project.

At this time of writing the api is only available through the download page, but I have send a maven upload request so soon it will be available from ibiblio.