How to add a barcode to a Jasper Reports template and have it save the data in a field?

From Jasper in the Palette panel select the Barcode option. Then drag the code to the desired location within the template.

Next, you must indicate the type of code to use:

Once you have selected the format, click on it, and go to Bacode. There you must add the name of the field with the content of your barcode.