Pick Custom Object from Select one menu JSF [duplicate] - jsf

Question

This question already has answers here:
How to populate options of h:selectOneMenu from database?
(5 answers)
Closed 6 years ago.
I want to pick a custom object from select one menu. It neither shows an error nor values. What should I do?
My xhtml document:
<h:panelGrid columns="2">
<p:outputLabel value="" />
<p:selectOneMenu id="CurrencyMenu" value="#{CurrencyMB.currency}" >
<f:selectItem itemLabel="-- Select Currency--" itemValue="#{null}"/>
<f:selectItems value="#{CurrencyMB.currencyList}" var="currency" itemValue="#{currency.currencyId}" itemLabel="#{currency.currencyName}" >
</f:selectItems>
<p:ajax update="currencyOut" />
</p:selectOneMenu>
<p:outputLabel value="Currency Id : #{CurrencyMB.currency.currencyId}" id="currencyOut" />
</h:panelGrid>
My managedBean class:
#ManagedBean(name = "CurrencyMB")
#RequestScoped
public class CurrencyManagedBean {
private Currency currency;
private List<Currency> currencyList;
public Currency getCurrency() {
return currency;
}
public void setCurrency(Currency currency) {
this.currency = currency;
}
public List<Currency> getCurrencyList() {
currencyList = new ArrayList<Currency>();
currencyList.addAll(getiCurrencyService().getCurrencies());
return currencyList;
}
public void setCurrencyList(List<Currency> currencyList) {
this.currencyList = currencyList;
}
}

Answer 1

You are trying to map a Java object of class Currency to a string that comes as a HTTP request parameter. A converter is intended to be used in a situation when you need to create an object from a its string representation, and vice versa, like in the situation you faced.
Basically there are two approaches.
1. Utilize converter.
With this approach you define item value as a Currency object and use a converter to create string representation from an object and recreate an object back from a string. For the converter part, just follow the tutorial Luiggi pointed at. Basically you need to create a class that implements Converter, annotate it with #FacesConverter("currencyConverter") to be able to refer to the converter by id, like in converter="currencyConverter" attribute of a JSF tag:
<p:selectOneMenu id="CurrencyMenu" value="#{CurrencyMB.currency}" converter="currencyConverter">
<f:selectItems value="#{CurrencyMB.currencyList}" var="currency" itemValue="#{currency}" itemLabel="#{currency.currencyName}" />
<p:ajax update="currencyOut" />
</p:selectOneMenu>
2. Utilize plain Strings (or java primitive wrappers).
With this approach you bind item values, as well as user selection to a bean property of String type, and not to an actual object. Using it this way you won't need any converter, and string values will be set for you:
<p:selectOneMenu id="CurrencyMenu" value="#{CurrencyMB.currencyName}">
<f:selectItems value="#{CurrencyMB.currencyList}" var="currency" itemValue="#{currency.currencyName}" itemLabel="#{currency.currencyName}" />
<p:ajax update="currencyOut" />
</p:selectOneMenu>
Finally, it is worth reading the question to the answer Why selectOneMenu Send ItemLabel to the converter?.

Answer 2

You can create Converter for your Custom Object Currency.
Step 1: Create a Converter class and Implement javax.faces.convert.Converter Interface,Override getAsObject and getAsString methods and write your logic for String to Object Conversion and Object to String Conversion.
Step 2: Simply declare something like #FacesConverter("currencyConverter") in your converter class or If you want use Spring Inject or Autowired Annotation in Converter class declare your Converter Class with #Component("currencyConverter") Annotation and don't use #FacesConverter.And your converter class should in component scan package.
Step 3: Declare your converter in Selectonemenu Using converter property.
If you still have any problem please refer this link
http://www.techpages.org/jsf/jsf-custom-object-converter-from-selectonemenu/2428/