java - Primefaces 选项列表转换器

Question

我正在使用 Primefaces 4.0 和 JSF 2.2。我使用带有转换器的选项列表。arg2问题是我的转换器没有得到正确的结果。它总是说0。我的期望是这是元素的 id，我可以将它从源/目标列表中解析出来。有任何想法吗？

我Converter的灵感来自How to write a custom converter for <p:pickList>。

我的 Picklist 声明如下：

<p:pickList value="#{loadingPlaceGroups.pickList}"
    style="margin:0" var="loadingPlace"
    converter="primeFacesPickListConverter"
    itemValue="#{loadingPlace}"
    itemLabel="#{loadingPlace.name}#{loadingPlace.location.address.street}#{loadingPlace.location.address.houseNr}#{loadingPlace.location.address.zipCode}#{loadingPlace.location.address.city}"
    showSourceFilter="true" showTargetFilter="true"
    filterMatchMode="contains"
    styleClass="picklist500x350source picklist500x350target">

    <f:facet name="sourceCaption">Alle Ladestellen</f:facet>
    <f:facet name="targetCaption">Gewählte Ladestellen</f:facet>
    <p:column style="border-bottom:1px solid lightgray">
        <p:panelGrid>
            <p:row>
                <p:column style="padding-left:0;font-size:12pt">
                    <h:outputLabel value="#{loadingPlace.name}"
                        style="font-weight:bold" />
                </p:column>
            </p:row>
            <p:row>
                <p:column style="padding:0">
                    <h:outputLabel
                        value="#{loadingPlace.location.address.street} #{loadingPlace.location.address.houseNr}" />
                </p:column>
            </p:row>
            <p:row>
                <p:column style="padding:0">
                    <h:outputLabel
                        value="#{loadingPlace.location.address.zipCode} #{loadingPlace.location.address.city}" />
                </p:column>
            </p:row>
        </p:panelGrid>
    </p:column>
</p:pickList>

Answer 1

对于选择列表，请使用generic converter：

import java.util.Map;
import java.util.Map.Entry;
import java.util.UUID;
import java.util.WeakHashMap;

import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.faces.convert.FacesConverter;

@FacesConverter(value = "entityConverter")
public class EntityConverter implements Converter {

    private static Map<Object, String> entities = new WeakHashMap<Object, String>();

    @Override
    public String getAsString(FacesContext context, UIComponent component, Object entity) {
        synchronized (entities) {
            if (!entities.containsKey(entity)) {
                String uuid = UUID.randomUUID().toString();
                entities.put(entity, uuid);
                return uuid;
            } else {
                return entities.get(entity);
            }
        }
    }

    @Override
    public Object getAsObject(FacesContext context, UIComponent component, String uuid) {
        for (Entry<Object, String> entry : entities.entrySet()) {
            if (entry.getValue().equals(uuid)) {
                return entry.getKey();
            }
        }
        return null;
    }

}