h:inputText return a empty string instead of NULL

Question

Hello, i make a JSF 2.0 Application and i use many h:inputText fields to input data in my database. Some fields are not required

<h:inputText value="#{registerBean.user.phoneNumber}" id="phoneNumber" >
                            <f:validateLength maximum="20" />
                        </h:inputText><br/>

When the user leave this field empty JSF returns "" instead of NULL.

How can i fix this behavior without check every String with

if(string.equals(""){ string = null}

Thanks.

Answer 1

You can configure JSF 2.x to interpret empty submitted values as null by the following context-param in web.xml (which has a pretty long name, that'll also be why I couldn't recall it ;) ):

<context-param>
    <param-name>javax.faces.INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL</param-name>
    <param-value>true</param-value>
</context-param>

---

For reference and for ones who are interested, in JSF 1.2 (and thus not 1.1 or older because it's by design not possible to have a Converter for java.lang.String) this is workaroundable with the following Converter:

public class EmptyToNullConverter implements Converter {

    public Object getAsObject(FacesContext facesContext, UIComponent component, String value) {
        if (value == null || value.trim().length() == 0) {
            if (component instanceof EditableValueHolder) {
                ((EditableValueHolder) component).setSubmittedValue(null);
            }
            return null;
        }
        return value;
    }

    public String getAsString(FacesContext facesContext, UIComponent component, Object value) {
        return (value == null) ? null : value.toString();
    }

}

...which needs to be registered in faces-config.xml as follows:

<converter>
    <converter-for-class>java.lang.String</converter-for-class>
    <converter-class>com.example.EmptyToNullConverter</converter-class>
</converter>

For JDK6 purists, the value.trim().length() == 0 can also be replaced by value.trim().isEmpty() ;)

Answer 2

Hello, i hope this is the righ way to say that i can't find a solution for the Problem.

I have add the context-param to my web.xml but it has no result. I use a Tomcat 6.0.24 Server with this two context-param: javax.faces.PROJECT_STAGE = Development javax.faces.VALIDATE_EMPTY_FIELDS = true