how to upload file in a form?

[staticose]

I found the below content in user guide:
We support the following form property types:

string (org.activiti.engine.impl.form.StringFormType)
long (org.activiti.engine.impl.form.LongFormType)
enum (org.activiti.engine.impl.form.EnumFormType)
date (org.activiti.engine.impl.form.DateFormType)
boolean (org.activiti.engine.impl.form.BooleanFormType)

but now, I want to upload a file within the form, how could I do this? Thanks!

[jbarrez]

That's not supported out of the box.You will need to implement a custom form property yourself: http://www.jorambarrez.be/blog/2013/03/13/creating-a-new-form-property-in-activiti/