h:inputText which is bound to String property is submitting empty string instead of null
I have a JSF 2.0 application on Tomcat with 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>
When the user leave this field empty JSF sets empty string "" instead of null.
How can I fix this behavior without checking every String with
if (string.equals("")) { string = null; }
Answer
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 EmptyToNullStringConverter implements Converter {
public Object getAsObject(FacesContext facesContext, UIComponent component, String submittedValue) {
if (submittedValue == null || submittedValue.isEmpty()) {
if (component instanceof EditableValueHolder) {
((EditableValueHolder) component).setSubmittedValue(null);
}
return null;
}
return submittedValue;
}
public String getAsString(FacesContext facesContext, UIComponent component, Object modelValue) {
return (modelValue == null) ? "" : modelValue.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.EmptyToNullStringConverter</converter-class>
</converter>
In case you're not on Java 6 yet, replace submittedValue.empty() by submittedValue.length() == 0.