primefaces如何从选择列表中检索更改的值

Question

我已经实现了以下选择列表：

<p:pickList id="pickList" value="#{reportConfiguratorBean.dualListVars}" var="cRVariable" itemValue="#{cRVariable}" itemLabel="#{cRVariable.varName}" converter="#{cRImageTypeConverter}" immediate="true" rendered="true" >
    <f:facet name="sourceCaption">Available Variables</f:facet>
    <f:facet name="targetCaption">Associated Variables</f:facet>                
</p:pickList>                       
<f:facet name="footer"> 
    <p:commandButton id='varassociate' action="#{reportConfiguratorBean.setAssocImTypVariables()}" value='Associate' process="@this,pickList" />
</f:facet>

选择列表已正确填充（使用数据库中的 getAssocImTypVariables()）。但我的问题是我无法捕获更改的选项列表值用户更改了源列表和目标列表。我正在尝试使用 commandButton 方法“setAssocImTypVariables”来捕获更改，如下所示：

public void setAssocImTypVariables() {      
    System.out.println(">>>>>>>>>>>>>>> entered");          
    List<CRVariable> sourceVariables = this.dualListVars.getSource();
    List<CRVariable> targetVariables = this.dualListVars.getTarget();       

    System.out.println(dualListVars.getSource());
    System.out.println(dualListVars.getTarget());

    for (CRVariable sourceVariable:sourceVariables) {
        System.out.println(">>>>>>>>>>>>> I am a source variable: " + sourceVariable.getVarName());
    }       
    for (CRVariable targetVariable:targetVariables) {
        System.out.println(">>>>>>>>>>>>> I am a target variable: " + targetVariable.getVarName());
    }       
    }

因此，例如，如果我有一个带有初始源 = (Obj1,Obj2,Obj3,Obj5,Obj7) 和目标 = (Obj4,Obj6) 的选项列表，我将“Obj1”从源移动到目标但在我的控制台中我得到：

--------- 输入 [] []

所以我的 dualListVars（源和目标）没有填充！我有两个用于源和目标的空列表...

所以我的方法无法感知选项列表的变化......有什么想法吗？ 我是 java + primefaces 的新手，所以它可能是非常基础的东西:(

我还附上了getAssocImTypesOnLoad()方法：

public void getAssocImTypesOnLoad() {               
    Long imTypeId = Long.parseLong(virtualId);      
    List<CRVariable> source;
    List<CRVariable> target;        
    Session session = HibernateUtil.getSessionFactory().openSession();
    Transaction tx = null;      
    try 
    {
        tx = session.beginTransaction();            
        String hq3 = "select distinct v from CRVariable v join v.crimagetypes t where t.id in (:itid)";
        Query query3 = session.createQuery(hq3);
        query3.setParameter("itid",imTypeId);
        target = query3.list();
        String hq4 = "select v FROM CRVariable v WHERE v.id not in (" +
                "select distinct v1.id " +
                "from CRVariable v1 " +
                "join v1.crimagetypes t2 " +
                "where t2.id in (:itid))";
        Query query4 = session.createQuery(hq4);
        query4.setParameter("itid",imTypeId);
        source = query4.list();
        dualListVars = new DualListModel<CRVariable>(source, target);
        tx.commit();
    } 
    catch (Exception e) 
    {
        if (tx != null) 
        {
            e.printStackTrace();
        }
    } 
    finally 
    {
       session.close();
    }
}

Answer 1

为什么要在commandButton 上使用immediate=true 属性？

如果我没记错的话，根据balusC的一篇文章 命令按钮上的check it out here 和immediate=true 应该跳过apply model to values phase。

也许这就是你的模型没有更新的原因？

（只是通过查看代码的猜测 - 我没有复制这个。）

Answer 2

仔细查看 primefaces 展示：Primefaces picklist

直接拨打dualListVars。 #{reportConfiguratorBean.dualListVars} 被解析为 reportConfiguratorBean.getDualListVars()，因为 dualListVars 是一个属性（例如，具有 getter 和 setter 的属性）。

<p:pickList id="pickList" value="#{reportConfiguratorBean.dualListVars}" var="cRVariable" itemValue="#{cRVariable}" itemLabel="#{cRVariable.varName}" converter="#{cRImageTypeConverter}" immediate="true" rendered="true" >
    <f:facet name="sourceCaption">Available Variables</f:facet>
    <f:facet name="targetCaption">Associated Variables</f:facet>                
</p:pickList> 

action 属性用于业务逻辑。您可以在此处查看源和目标列表。 process 属性告诉 JSF 要处理哪些组件。在您的情况下，您希望处理组件 picklist 和 commandButton。您也可以使用process="@form" 处理整个表单。

<p:commandButton id='varassociate' action="#{reportConfiguratorBean.readMyAssocImTypVariables}" value='Associate' ajax='false' process="@this,pickList" immediate="true" />

readMyAssocImTypVariables 函数：

 public void readMyAssocImTypVariables() {      
    List<CRVariable> sourceVariables = this.dualListVars.getSource();
    List<CRVariable> targetVariables = this.dualListVars.getTarget();       
    for (CRVariable sourceVariable:sourceVariables) {
        System.out.println(">>>>>>>>>>>>> I am a source variable: " + sourceVariable.getVarName());
    }       
    for (CRVariable targetVariable:targetVariables) {
        System.out.println(">>>>>>>>>>>>> I am a target variable: " + targetVariable.getVarName());
     }       
  }

无关： 不要将业务逻辑放入 getter/setter 中！ JSF 多次调用它们。

Answer 3

一个正在运行的选项列表示例 picklist.xhtml

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:p="http://primefaces.org/ui"
xmlns:ui="http://java.sun.com/jsf/facelets">


<h:head></h:head>

<h:body>
<h:form>
    <h3>Basic PickList</h3>
    <p:pickList value="#{pickListBean.cities}" var="city"
        itemLabel="#{city}" itemValue="#{city}" />
<p:commandButton  value="Submit" action="#{pickListBean.displayList}" />    


</h:form>

</h:body>
</html>   

PickListBean.java

import java.util.ArrayList;
import java.util.List;

import javax.faces.bean.ManagedBean;
import org.primefaces.model.DualListModel;

@ManagedBean
public class PickListBean {

   private DualListModel<String> cities;

   public PickListBean() {

  //Cities
  List<String> citiesSource = new ArrayList<String>();
  List<String> citiesTarget = new ArrayList<String>();

  citiesSource.add("Istanbul");
  citiesSource.add("Ankara");
  citiesSource.add("Izmir");
  citiesSource.add("Antalya");
  citiesSource.add("Bursa");
//  citiesTarget.add("T1");


  cities = new DualListModel<String>(citiesSource, citiesTarget);
   }

   public DualListModel<String> getCities() {
      return cities;
   }
   public void setCities(DualListModel<String> cities) {
      this.cities = cities;
   }
   public void displayList(){

     System.out.println("values in list are" +cities.getTarget());


   }


}