Java 验证错误：值是列表选择事件的必需错误 背景

选择项目列表时，使用Ajax向web服务器触发事件。元素是一个JSF

rich:orderingList

项

问题 必须接收事件的类：

public class BusinessAreaListHandler extends ListHandler<ListElement> {
  private static final long serialVersionUID = -581048454118449233L;

  public BusinessAreaListHandler() { load(); }
  public List<ListElement> getBusinessAreas() { return getList(); }
  public Set<ListElement> getSelection() { return getSet(); }

  public void select() {
    System.out.println( "Clicked Element" );
  }

  protected void load() {
    appendList( new ListElement( "employee" ) );
    appendList( new ListElement( "company" ) );
    appendList( new ListElement( "payroll" ) );
  }
}

列表转换器

：

public class ListConverter implements Converter {
  @Override
  public Object getAsObject( FacesContext fc, UIComponent ui, String value ) {
    ListElement result = new ListElement( value );
    int index = value.lastIndexOf( ListElement.SEPARATOR );

    System.out.println( "Convert FROM: " + value );

    if( index > 0 ) {
      String id = value.substring( 0, index );
      String v = value.substring( index + 1 );
      result = new ListElement( id, v );
    }

    System.out.println( "Convert TO  : " + result.toString() );

    return result;
  }

  @Override
  public String getAsString( FacesContext fc, UIComponent ui, Object value ) {
    return value.toString();
  }
}

设置列表和事件操作的XHTML片段：

<h:panelGrid columns="2">
  <h:panelGroup>
    <rich:orderingList value="#{businessAreas.list}" var="businessArea" converter="businessAreaConverter" immediate="true" orderControlsVisible="false" fastOrderControlsVisible="false" selection="#{businessAreas.selection}" id="BusinessAreas">
      <f:facet name="caption">
        <h:outputText value="Business Areas" />
      </f:facet>
      <rich:column>
        <h:outputText value="#{businessArea}" />
      </rich:column>
      <a4j:support event="onclick" ignoreDupResponses="true" requestDelay="500" action="#{businessAreas.select}" reRender="ColumnClusters" />
      <a4j:support event="onkeyup" ignoreDupResponses="true" requestDelay="500" action="#{businessAreas.select}" reRender="ColumnClusters" />
    </rich:orderingList>
  </h:panelGroup>
  <h:panelGroup>
    <rich:listShuttle sourceValue="#{columnClusters.list}" targetValue="#{domainContent.list}" var="columnCluster" converter="columnClusterConverter" sourceRequired="false" targetRequired="true" moveControlsVisible="true" orderControlsVisible="false" fastOrderControlsVisible="false" sourceCaptionLabel="Column Clusters" targetCaptionLabel="Domain Content" copyTitle="Move" copyControlLabel="Move" copyAllControlLabel="Move All" copyAllTitle="Move All" id="ColumnClusters">
      <rich:column>
        <h:outputText value="#{columnCluster}" />
      </rich:column>
    </rich:listShuttle>
  </h:panelGroup>
  <h:panelGroup>
    <h:commandButton action="action" value="Create Domain" />
  </h:panelGroup>
</h:panelGrid>

问题: 当用户选择（或取消选择）项目时，需要什么来触发对

BusinessAreaListHandler

中

select（）

的调用

工具书类

---

谢谢大家!

问题在于此属性：

targetRequired="true"

---

由于单击会立即触发对服务器的Ajax请求，因此右侧的穿梭机（目标）应该有数据。如果没有数据，将发布验证错误。

谢谢。代码是正确的；我缺少开头和结尾的

表单

元素。然而，现在我得到了臭名昭著的

验证错误：Value是required

错误。它看起来很好。您确实有hashCode（）和equals（）。对于hashCode（）和equals（），我通常让IDE（在我的例子中是Eclipse）生成它们。也许可以尝试一下？触发了

onclick

事件，但是在

select（）

代码运行之前，遇到了一个错误。我让Eclipse生成

hashCode（）

和

equals（）

方法。同样的错误也会发生。@Dave:如果你给我发了一个WAR文件（带源代码），我会试着运行它。通过

New Element (Hash:Value): 1193469614:employee
New Element (Hash:Value): 950484093:company
New Element (Hash:Value): -786522843:payroll
New Element (Hash:Value): 3373707:name
New Element (Hash:Value): -1147692044:address
New Element (Hash:Value): 114603:tax
New Element (Hash:Value): 1193469614:employee
Convert FROM: employee
Convert TO  : employee
New Element (Hash:Value): 950484093:company
Convert FROM: company
Convert TO  : company
New Element (Hash:Value): -786522843:payroll
Convert FROM: payroll
Convert TO  : payroll
New Element (Hash:Value): 3373707:name
Convert FROM: name
Convert TO  : name
New Element (Hash:Value): -1147692044:address
Convert FROM: address
Convert TO  : address
New Element (Hash:Value): 114603:tax
Convert FROM: tax
Convert TO  : tax

targetRequired="true"