Java Platform, Enterprise Edition (Java EE) 8 The Java EE Tutorial

## Registering a Custom Converter

As is the case with a custom validator, if the application developer creates a custom converter, you must register it with the application either by using the `@FacesConverter` annotation, as described in Creating a Custom Converter, or by using the `converter` XML element in the application configuration resource file. Here is a hypothetical `converter` configuration for `CreditCardConverter` from the Duke’s Bookstore case study:

    <converter>
        <description>
            Converter for credit card numbers that normalizes
            the input to a standard format
        </description>
        <converter-id>CreditCardConverter</converter-id>
        <converter-class>
            dukesbookstore.converters.CreditCardConverter
        </converter-class>
    </converter>

Attributes specified in a `converter` tag override any settings in the `@FacesConverter` annotation.

The `converter` element represents a `javax.faces.convert.Converter` implementation and contains required `converter-id` and `converter-class` elements.

The `converter-id` element identifies an ID that is used by the `converter` attribute of a UI component tag to apply the converter to the component’s data. Using a Custom Converter includes an example of referencing the custom converter from a component tag.

The `converter-class` element identifies the `Converter` implementation.

Creating and Using a Custom Converter explains how to create a custom converter.

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