Avoid creating the same object twice when updating in JSF

Question

Let's say we have the “add a new object” form in AddObject.jspx, and the Confirm.jsp page (something like an object with identifier NN was added to the database ...)

in faces-config.xml:

<navigation-rule>
    <from-view-id>/AddObject.jsp</from-view-id>
    <navigation-case>
        <from-outcome>add</from-outcome>
        <to-view-id>/Confirm.jsp</to-view-id>
    </navigation-case>
</navigation-rule>

Thus, the user opens AddObject.jsp, fills out the form and clicks the Add button, which launches the event handler in the AddObject bean support. Support bean inserts a new object into the database and returns the result "add". Thus, we get to the confirmation screen.

Now, if I press F5 (refresh browser), a new object will be created, and the confirmation screen will be displayed again with the new identifier of the new object. I can continue to attack F5 and get as many new objects as I want.

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Answer 1

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 POST this request

 GET this confirmation page

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