JSF trimming white spaces

Question

HI,

I have an input field in which I want to trim any leading/trailing whitespaces. We are using JSF and binding the input field to a backing bean in the jsp using:

<h:inputText id="inputSN" value="#{regBean.inputSN}" maxlength="10"/>

My question is that besides validation can this be done in the jsp? I know we can also do this using the trim() java function in the Handler, but just wondering if there is a more elegant way to achieve this in JSF.

Thanks.

Solution 1

You could use a Converter (tutorial).

Solution 2

As suggested by McDowell and BalusC, you can create a Converter, and register it with @FacesConvert annotation for the String class. And then in the getAsObject method check the UIComponent type and apply the trimming only for the HtmlInputText components.

@FacesConverter(forClass = String.class)
public class StringTrimConverter implements Serializable, javax.faces.convert.Converter {

    @Override
    public Object getAsObject(FacesContext context, UIComponent cmp, String value) {

        if (value != null && cmp instanceof HtmlInputText) {
            // trim the entered value in a HtmlInputText before doing validation/updating the model
            return value.trim();
        }

        return value;
    }

    @Override
    public String getAsString(FacesContext context, UIComponent cmp, Object value) {

        if (value != null) {
            // return the value as is for presentation
            return value.toString();
        }
        return null;
    }

}

Solution 3

I answered a similar question here

Basically you can either create your own component that is a copy of inputText which automatically trims, or you can extend the inputText and add trim attribute that trims if true.

Solution 4

I resolved this by just using the trim() function in the handler before doing any processing. it just seemed like the most straight forward way of doing this.

View more solutions

Comments

[BalusC]

And register it with converter-for-class for java.lang.String so that you don't need to define it on every UIInput component.

[McDowell]

@Martlark - it is an element used in faces-config.xml. From spec: /faces-config/converter -- Create or replace a converter id/converter class or target class/converter class pair with the Application instance for this web application. Also: The “converter-for-class” element represents the fully qualified class name for which a Converter class will be registered. See the JSF specification for more.

[Jasper de Vries]

Or, if you don't feel like coding it yourself, see showcase.omnifaces.org/converters/TrimConverter

[Kawu]

I personally feel THE ABOVE COMMENT should be the accepted answer