primefaces autocomplete with pojo

问题

I read on SO some QA about the same component, but I feel I'm missing something, because I am one step behind. I can't even make the page open when using the primefaces autocomplete component in it. The snippet for it is:

<p:autoComplete value="#{indirizzoCtrl.selectedCodiceNazione}"  
            completeMethod="#{indirizzoCtrl.completeNazione}"  
            var="nazione" itemLabel="#{nazione.nome}"   
            itemValue="#{nazione.codiceNazione}" />

Nazione is a Pojo class where CodiceNazione and Nome are two String field (with getter and setter for sure). completeNazione is a method on the ManagedBean that returns List<Nazione>. Looking at BalusC explanation here, it seems to me that i don't need any converter involved, because both itemValue and value attributes are mapped to string property. Anyway, when I just open the page containing this autocomplete snippet, it crashes with this error:

javax.el.PropertyNotFoundException: /Cliente/Indirizzo.xhtml @23,56 itemValue="#{nazione.codiceNazione}": itemValue="#{nazione.codiceNazione}": Property 'codiceNazione' not found on type java.lang.String

Why this is happening? I really can't get it. The method completeNazione hasn't even called yet, so it shouldn't know any Nazione yet. What's wrong with it?

Edited: Following the suggestion, I tried to add a converter, but I still get the same error. Here's my converter:

    public class NazioneConverter implements Converter {

    final static Logger log = Logger.getLogger(NazioneConverter.class);

    @Override
    public Object getAsObject(FacesContext context, UIComponent component, String value) {
        if (value.trim().equals("")) {  
            return null;  
        } else {  
            try {  
                IndirizzoRepository ir = new IndirizzoRepository();
                List<Nazione> nazioni = ir.getNazioneByName(value);
                if (nazioni.size()==1) return nazioni.get(0);
                else throw new Exception();

            } catch (Exception e) {
                String msg = "Errore di conversione";
                log.error(msg, e);
                throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, msg, "Non è una nazione conosciuta"));  
            }  
        }          
    }

    @Override
    public String getAsString(FacesContext context, UIComponent component, Object value) {
        if (value == null || value.equals("")) {  
            return "";  
        } else {  
            return String.valueOf(((Nazione) value).getNome());  
        } 
    }

}

now the component in the view looks like:

<p:autoComplete value="#{indirizzoCtrl.indirizzo.nazione.codiceNazione}"  
            completeMethod="#{indirizzoCtrl.completeNazione}"  
            var="nazione" itemLabel="#{nazione.nome}" converter="#{nazioneConverter}"
            itemValue="#{nazione.codiceNazione}" forceSelection="true"  />

But still don't working. The converter is not even invoked: I registered it in my faces-config.xml file. I also tried itemValue="#{nazione}" as in the primefaces showcase but the problem became the ItemLabel attribute, mapped to nazione.nome. What am I doing wrong?

回答1:

This worked for me:

//Converter
@FacesConverter(value="MarcaConverter")
public class MarcaConverter implements Converter{
    MarcaDAO marcaDAO;
    public Object getAsObject(FacesContext contet, UIComponent component, String value) {
        if(value==null || value.equals(""))
            return null;
        try{
            int id = Integer.parseInt(value);
            return marcaDAO.findMarcaById(id);
        }catch (Exception e) {
            e.printStackTrace();
            throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, "Marca no válida", ""));
        }
    }

    public String getAsString(FacesContext contet, UIComponent component, Object value) {
        if(value==null || value.equals(""))
            return null;
        return String.valueOf(((Marca)value).getCodigoMarca());
    }
}




//--------------------------------------
//Bean
@ManagedBean
@ViewScoped
public class MyBeans implements Serializable{
    private Marca marca;
    ...
    public Marca getMarca(){
        return marca;
    }
    public void setMarca(Marca m){
        marca=m;
    }
    ...
    public List<Marca> obtenerMarcasVehiculos(String s) {
        List<Marca> marcas,smarcas=new ArrayList<Marca>();
        try{
            marcas= marcaDAO.findAllMarcas();
            if(s.trim().equals("")) return marcas;
            for(Marca m:marcas)
                if (m.getNombreMarca().toString().contains(s) || m.getNombreMarca().toLowerCase().contains(s.toLowerCase())) {
                    smarcas.add(m);
                }
            return smarcas;
        }catch(Exception e){
            //JsfUtil.showFacesMsg(e,"Error al obtener las marcas de veh&iacute;culos","",FacesMessage.SEVERITY_WARN);
            e.printStackTrace();
            JsfUtil.lanzarException(e);
            return null;
        }
    }


//-----------------------------------------
//*.xhtml page
...
    <p:autoComplete 
       id="cbxMarca" value="#{myBean.marca}" size="40"
       converter="MarcaConverter"
       completeMethod="#{myBean.obtenerMarcasVehiculos}"
       var="m" itemLabel="#{m.nombreMarca}" itemValue="#{m}"
       forceSelection="true" dropdown="true"
       required="true" scrollHeight="200">
    </p:autoComplete>
...

//-----------------------------------------
//Class Marca
public class Marca implements Serializable{
       private static final long serialVersionUID = 1L;

    private Integer codigoMarca;
    private String nombreMarca;
        ...

回答2:

Have you read the user guide? http://www.primefaces.org/documentation.html

I must say I have never used the autocomplete with pojo but from what I've read in the user guide, Çağatay Çivici says there:

Note that when working with pojos, you need to plug-in your own converter.

Here you can find out that a converter (PlayerConverter) is implemented even if player.name and of the other props are Strings.

I admit this is interesting and I'll do some research but I don't have the necessary time right now...

回答3:

Change converter="#{nazioneConverter}" to converter="nazioneConverter" in autocomplete

回答4:

Change the itemValue from itemValue="#{nazione.codiceNazione}" to itemValue="#{nazione}" in autoComplete.

来源：https://stackoverflow.com/questions/8560073/primefaces-autocomplete-with-pojo