PropertyUtils.copyProperties

[Matt Raible]

We have the following architecture/flow:   components: List.jsp EditAction.java EntityForm.java (contains get/set for action, get/set for EntityDO) EntityDO.java Detail.jsp SaveAction.java   A user clicks on a link in List.jsp to view the details of an item. The EditAction servlet creates an EntityDO and puts it into the session and the EntityForm.       PropertyUtils.setNestedProperty(form, "DO", createdDO);   The Detail.jsp displays the form elements from the DO just fine. The SaveAction servlet is called when the user submits changes from the form. The SaveAction servlet grabs the DO from the session and uses the following line to copy elements from the form into the DO from the session       PropertyUtils.copyProperties(sessionDO, PropertyUtils.getNestedProperty(form,"DO"));   The problem I am having is that I want ONLY the elements from the form that are displayed on the screen to be copied into the sessionDO - HOWEVER, it is copying ALL DO attributes - and many of them are getting set to their default values.   What I would like is that the sessionDO retains all values that are not displayed in the form.  The weird thing is that some values are retained from the session, but some are not - and the form seems to be resetting some values.   I hope I am doing something wrong and this can be fixed.  My workaround in the meantime is to put all DO attributes as hidden fields in the form, but this seems like a real pain.   Thanks,   Matt