JSF Tip #46 - Creating a custom converter

Sometimes you need to write a custom converter to converter the client side representation to an object instance and vice versa. What is needed to use a custom converter? See below.

A custom converter


    package customconverter;

    import javax.faces.component.UIComponent;
    import javax.faces.context.FacesContext;
    import javax.faces.convert.Converter;
    import javax.faces.convert.FacesConverter;

    @FacesConverter(value = "customConverterId")
    public class CustomConverter implements Converter {

        @Override
        public Object getAsObject(FacesContext context, UIComponent component, String value) {
            return new Custom();
        }

        @Override
        public String getAsString(FacesContext context, UIComponent component, Object value) {
            return value.toString();
        }
    }

And the page using it


    <?xml version='1.0' encoding='UTF-8'?>

    <!DOCTYPE html>

    <html xmlns="http://www.w3.org/1999/xhtml"
          xmlns:h="http://java.sun.com/jsf/html"
          xmlns:f="http://java.sun.com/jsf/core">
        <h:head>
            <title>Custom Converter - f:converter tag</title>
        </h:head>
        <h:body>
            <h2>Custom Converter - f:converter tag</h2>
            <p>
                Below you will see a string that was generated using a custom converter
                named 'customConverterId'. See the sources for the source for this
                converter.
            </p>
            <h:outputText value="#{customConverterBean.custom}">
                <f:converter converterId="customConverterId"/>
            </h:outputText>
        </h:body>
    </html>

Posted November 25, 2013