如何在jsf数据表中访问Map键

Question

javax.el.PropertyNotFoundException: /member/apps/cms/edit.xhtml @228,49 value="#{props.key}": Property 'key' not found on type java.util.HashMap$Values尝试显示以下数据表时出现错误。

<p:dataTable id="properties" var="props" value="#{contentEditorBacking.properties}" editable="true">

    <p:column headerText="Property">
        <p:cellEditor>
            <f:facet name="output"> 
                <h:outputText value="#{props.key}" />
            </f:facet>
            <f:facet name="input">
                <h:inputText value="#{props.key}" />
            </f:facet>
        </p:cellEditor>
    </p:column>
    <p:column headerText="Value">
        <p:cellEditor>
                        <f:facet name="output"> 
                <h:outputText value="#{props.value}" />
            </f:facet>
            <f:facet name="input">
                <h:inputText value="#{props.value}" />
            </f:facet>
        </p:cellEditor>
    </p:column>

    <p:column headerText="Edit">
        <p:rowEditor />
        <!-- Need to put an update on here yet -->
        <p:commandLink styleClass="ui-icon ui-icon-trash" id="deleteProperty" actionListener="#{contentEditorBacking.deleteProperty}">
                 <f:attribute name="key" value="#{props.key}" />
             </p:commandLink>
    </p:column>
</p:dataTable>

这是我的contentEditorBacking的相关部分：

@ManagedBean
@ViewScoped
public class ContentEditorBacking {
    private Map<String, Properties> properties = new LinkedHashMap<String, Properties>();

    public Collection<Properties> getProperties() throws Exception{
        return properties.values();
    }

    public static class Properties{

        private String key;
        private String value;

        public Properties(String key, String value) {
            super();
            this.key = key;
            this.value = value;
        }

        public String getKey() {
            return key;
        }
        public void setKey(String key) {
            this.key = key;
        }
        public String getValue() {
            return value;
        }
        public void setValue(String value) {
            this.value = value;
        }
        @Override
        public String toString() {
            return "key=" + key + ", value=" + value + "";
        }

    }
}

如何从属性图访问键值？

Answer 1

在即将发布的JSF 2.2之前，<h:dataTable>/
<p:dataTable>不支持Collection<E>。它仅支持其他功能List<E>。

您需要更换

public Collection<Properties> getProperties() throws Exception{
    return properties.values();
}

通过

private List<Properties> propertiesAsList;

public List<Properties> getProperties() throws Exception{
    return propertiesAsList;
}

然后在地图初始化后的某个地方执行此操作

propertiesAsList = new ArrayList<Properties>(properties.values());

（注意：不要在吸气剂中做！）