Jsf 2 如何在jsf中从selectOneMenu中获取所选项目值的id？

我有分类的下拉列表。在选择特定类别时，我已经呈现了该类别子类别的另一个下拉列表。我需要所选子类别的id。但我无法获取它。我的代码是：

 <tr>
     <td align="right">
          <h:outputText value="Select Main Category:"></h:outputText>
     </td>
     <td>
          <h:selectOneMenu id="cmbcategory" value="#{categoryBean.categoryID}" required="true" requiredMessage="Select Category" >
               <f:selectItem itemLabel="--Select Category--" itemValue="0"></f:selectItem>
               <f:selectItems value="#{categoryBean.categories}" var="item" itemLabel="#{item.categoryName}" itemValue="#{item.categoryID}"></f:selectItems>
               <f:ajax event="valueChange" render="cmbsubcategory"  immediate="true" listener="#{categoryBean.SubcategoriesByCategory()}"/>
          </h:selectOneMenu>
     </td>
     <td><h:message for="cmbcategory"></h:message></td>
 </tr>
 <tr>
      <td align="right">
          <h:outputText value="Select Sucategory:"></h:outputText>
      </td>
      <td>
           <h:selectOneMenu id="cmbsubcategory" value="#{categoryBean.subCategoryID}" required="true" requiredMessage="Select Subcategory">
                <f:selectItem itemLabel="--Select Subcategory--" itemValue="0"></f:selectItem>
                <f:selectItems value="#{categoryBean.SubcategoriesByCategory()}" var="item" itemLabel="#{item.subcategoryID}" itemValue="#{item.subcategoryID}"></f:selectItems>

           </h:selectOneMenu>
      </td>
      <td><h:message for="cmbsubcategory"></h:message></td>
 </tr>    

public int getCategoryID() {
        return CategoryID;
    }

    public void setCategoryID(int CategoryID) {
        this.CategoryID = CategoryID;
    }


    public String getCategoryName() {
        return CategoryName;
    }

    public void setCategoryName(String CategoryName) {
        this.CategoryName = CategoryName;
    }

    public Collection<Category> getCategories() {
        categories=abr.getAllCategory();
        return categories;
    }

    public Collection<Subcategory> SubcategoriesByCategory()
    {
        System.out.print("catid...... "+CategoryID);
        subcats= abr.searchAllSubcategoriesByCategory(CategoryID);

        return subcats;

//            +"size....."+ subcats.size());
     }

    public String getSubCatName() {
        return SubCatName;
    }

    public void setSubCatName(String SubCatName) {
        this.SubCatName = SubCatName;
    }

    public int getSubCategoryID() {
        System.out.print("subcatid...... "+SubCategoryID);
        return SubCategoryID;
    }

    public void setSubCategoryID(int SubCategoryID) {
        this.SubCategoryID = SubCategoryID;
    }

    public Collection<Subcategory> getSubcats() {
        return subcats;
    }

    public void setSubcats(Collection<Subcategory> subcats) {
        this.subcats = subcats;
    }



    public void setCategories(Collection<Category> categories) {
        this.categories = categories;
    }

我的豆豆是：

public int getCategoryID() {
        return CategoryID;
    }

    public void setCategoryID(int CategoryID) {
        this.CategoryID = CategoryID;
    }


    public String getCategoryName() {
        return CategoryName;
    }

    public void setCategoryName(String CategoryName) {
        this.CategoryName = CategoryName;
    }

    public Collection<Category> getCategories() {
        categories=abr.getAllCategory();
        return categories;
    }

    public Collection<Subcategory> SubcategoriesByCategory()
    {
        System.out.print("catid...... "+CategoryID);
        subcats= abr.searchAllSubcategoriesByCategory(CategoryID);

        return subcats;

//            +"size....."+ subcats.size());
     }

    public String getSubCatName() {
        return SubCatName;
    }

    public void setSubCatName(String SubCatName) {
        this.SubCatName = SubCatName;
    }

    public int getSubCategoryID() {
        System.out.print("subcatid...... "+SubCategoryID);
        return SubCategoryID;
    }

    public void setSubCategoryID(int SubCategoryID) {
        this.SubCategoryID = SubCategoryID;
    }

    public Collection<Subcategory> getSubcats() {
        return subcats;
    }

    public void setSubcats(Collection<Subcategory> subcats) {
        this.subcats = subcats;
    }



    public void setCategories(Collection<Category> categories) {
        this.categories = categories;
    }

public int getCategoryID（）{
返回类别ID；
}
public void setCategoryID（int CategoryID）{
this.CategoryID=CategoryID；
}
公共字符串getCategoryName（）{
返回类别名称；
}
公共无效setCategoryName（字符串CategoryName）{
this.CategoryName=CategoryName；
}
公共集合getCategories（）{
categories=abr.getAllCategory（）；
退货类别；
}
公共集合子类别ByCategory（）
{
系统输出打印（“catid…”+类别ID）；
子类别=abr.searchAllSubcategoriesByCategority（CategoryID）；
返回子类别；
//+“大小…”+subcats.size（））；
}
公共字符串getSubCatName（）{
返回子目录名；
}
public void setSubCatName（字符串SubCatName）{
this.SubCatName=SubCatName；
}
public int getSubcategory id（）{
系统输出打印（“子类别…”+子类别ID）；
返回子类别ID；
}
public void setSubCategoryID（int SubCategoryID）{
this.SubCategoryID=子类别ID；
}
公共集合getSubcats（）{
返回子类别；
}
公共作废集合子类别（集合子类别）{
this.subcats=子类别；
}
公共集合类别（集合类别）{
这个。类别=类别；
}

您将属性获取程序与操作方法混为一谈。getter应该返回属性，而action方法应该是

void

或返回

String

public int getCategoryID() {
        return CategoryID;
    }

    public void setCategoryID(int CategoryID) {
        this.CategoryID = CategoryID;
    }


    public String getCategoryName() {
        return CategoryName;
    }

    public void setCategoryName(String CategoryName) {
        this.CategoryName = CategoryName;
    }

    public Collection<Category> getCategories() {
        categories=abr.getAllCategory();
        return categories;
    }

    public Collection<Subcategory> SubcategoriesByCategory()
    {
        System.out.print("catid...... "+CategoryID);
        subcats= abr.searchAllSubcategoriesByCategory(CategoryID);

        return subcats;

//            +"size....."+ subcats.size());
     }

    public String getSubCatName() {
        return SubCatName;
    }

    public void setSubCatName(String SubCatName) {
        this.SubCatName = SubCatName;
    }

    public int getSubCategoryID() {
        System.out.print("subcatid...... "+SubCategoryID);
        return SubCategoryID;
    }

    public void setSubCategoryID(int SubCategoryID) {
        this.SubCategoryID = SubCategoryID;
    }

    public Collection<Subcategory> getSubcats() {
        return subcats;
    }

    public void setSubcats(Collection<Subcategory> subcats) {
        this.subcats = subcats;
    }



    public void setCategories(Collection<Category> categories) {
        this.categories = categories;
    }

改变

public int getCategoryID() {
        return CategoryID;
    }

    public void setCategoryID(int CategoryID) {
        this.CategoryID = CategoryID;
    }


    public String getCategoryName() {
        return CategoryName;
    }

    public void setCategoryName(String CategoryName) {
        this.CategoryName = CategoryName;
    }

    public Collection<Category> getCategories() {
        categories=abr.getAllCategory();
        return categories;
    }

    public Collection<Subcategory> SubcategoriesByCategory()
    {
        System.out.print("catid...... "+CategoryID);
        subcats= abr.searchAllSubcategoriesByCategory(CategoryID);

        return subcats;

//            +"size....."+ subcats.size());
     }

    public String getSubCatName() {
        return SubCatName;
    }

    public void setSubCatName(String SubCatName) {
        this.SubCatName = SubCatName;
    }

    public int getSubCategoryID() {
        System.out.print("subcatid...... "+SubCategoryID);
        return SubCategoryID;
    }

    public void setSubCategoryID(int SubCategoryID) {
        this.SubCategoryID = SubCategoryID;
    }

    public Collection<Subcategory> getSubcats() {
        return subcats;
    }

    public void setSubcats(Collection<Subcategory> subcats) {
        this.subcats = subcats;
    }



    public void setCategories(Collection<Category> categories) {
        this.categories = categories;
    }

public Collection<Subcategory> SubcategoriesByCategory() {
  ..
}

并在ajax请求中调用此方法：

public int getCategoryID() {
        return CategoryID;
    }

    public void setCategoryID(int CategoryID) {
        this.CategoryID = CategoryID;
    }


    public String getCategoryName() {
        return CategoryName;
    }

    public void setCategoryName(String CategoryName) {
        this.CategoryName = CategoryName;
    }

    public Collection<Category> getCategories() {
        categories=abr.getAllCategory();
        return categories;
    }

    public Collection<Subcategory> SubcategoriesByCategory()
    {
        System.out.print("catid...... "+CategoryID);
        subcats= abr.searchAllSubcategoriesByCategory(CategoryID);

        return subcats;

//            +"size....."+ subcats.size());
     }

    public String getSubCatName() {
        return SubCatName;
    }

    public void setSubCatName(String SubCatName) {
        this.SubCatName = SubCatName;
    }

    public int getSubCategoryID() {
        System.out.print("subcatid...... "+SubCategoryID);
        return SubCategoryID;
    }

    public void setSubCategoryID(int SubCategoryID) {
        this.SubCategoryID = SubCategoryID;
    }

    public Collection<Subcategory> getSubcats() {
        return subcats;
    }

    public void setSubcats(Collection<Subcategory> subcats) {
        this.subcats = subcats;
    }



    public void setCategories(Collection<Category> categories) {
        this.categories = categories;
    }

<f:ajax .. listener="#{categoryBean.searchSubcats}"/>

然后，第二个drow down中的selectItems需要引用子类别的getter：

public int getCategoryID() {
        return CategoryID;
    }

    public void setCategoryID(int CategoryID) {
        this.CategoryID = CategoryID;
    }


    public String getCategoryName() {
        return CategoryName;
    }

    public void setCategoryName(String CategoryName) {
        this.CategoryName = CategoryName;
    }

    public Collection<Category> getCategories() {
        categories=abr.getAllCategory();
        return categories;
    }

    public Collection<Subcategory> SubcategoriesByCategory()
    {
        System.out.print("catid...... "+CategoryID);
        subcats= abr.searchAllSubcategoriesByCategory(CategoryID);

        return subcats;

//            +"size....."+ subcats.size());
     }

    public String getSubCatName() {
        return SubCatName;
    }

    public void setSubCatName(String SubCatName) {
        this.SubCatName = SubCatName;
    }

    public int getSubCategoryID() {
        System.out.print("subcatid...... "+SubCategoryID);
        return SubCategoryID;
    }

    public void setSubCategoryID(int SubCategoryID) {
        this.SubCategoryID = SubCategoryID;
    }

    public Collection<Subcategory> getSubcats() {
        return subcats;
    }

    public void setSubcats(Collection<Subcategory> subcats) {
        this.subcats = subcats;
    }



    public void setCategories(Collection<Category> categories) {
        this.categories = categories;
    }

<f:selectItems value="#{categoryBean.subcats}" ... />

我可以在的值中调用方法吗？

value

属性采用一个ValueExpression（它是一个具有相应getter和setter的bean属性）。但不能将操作方法设置为

值

。