I don't know what you mean by editing the content. If you look at some existing code in CSNS (e.g. email notification in CreateTopicController), the typical way to do it is to create an email template with some tokens (i.e. placeholders) like @forum.name@, inject the template to a controller as a bean, create a SimpleMailMessage from the template with the tokens replaced with the actual values, then send the message out.