Question

之前发表了关于此主题的帖子（Display values in drill-down SelectOneMenus）。我最初想到的问题是没有连接到Object转换器。

我有两个selectOneMenu相互依赖，扇区 - ＆gt;类别。当我持久保存Sector和Category的后台业务对象时，一切都按预期工作。即使当前用户会话终止并且用户再次登录并编辑以前保存的业务对象。

当实体管理器刷新对象并且用户想要再次从数据库中显示扇区，类别时，会出现问题。扇区selectOneMenu显示其应有的值，但不显示类别selectOneMenu值。虽然辅助bean具有数据库中的正确值。

是什么使selectOneMenu在从数据库而不是从内存加载时不显示某些持久值/对象？

Edit.xhtml

<h:outputLabel value="Sector:" />
<h:selectOneMenu id="sectorSelector" value="#{activityController.selected.category.sector}" title="#{bundle.CreateSectorLabel_sectorName}" valueChangeListener="#{activityController.changeSectorMenu}" immediate="true">
            <a4j:ajax event="change" execute="@this categoryMenu" render="categoryMenu"/>
            <f:selectItems value="#{sectorController.itemsAvailableSelectOne}"/>
</h:selectOneMenu>

<h:outputLabel value="Category:" />
    <h:selectOneMenu id="categoryMenu" value="#{activityController.selected.category}" title="#{bundle.CreateSectorLabel_sectorName}" 
        binding="#{activityController.categoryMenu}"
            required="true" requiredMessage="#{bundle.CreateCategoryRequiredMessage_sector}">                        
    <f:selectItems value="#{activityController.categorySelection}"/>
</h:selectOneMenu>

类别

的控制器bean

@ManagedBean(name = "categoryController")
@SessionScoped
public class CategoryController implements Serializable{

    ....

    @FacesConverter(forClass = Category.class)
    public static class CategoryControllerConverter implements Converter {

        @Override
        public Object getAsObject(FacesContext facesContext, UIComponent component, String value) {
            if (value == null || value.length() == 0) {
                return null;
            }
            CategoryController controller = (CategoryController) facesContext.getApplication().getELResolver().
                    getValue(facesContext.getELContext(), null, "categoryController");
            return controller.ejbFacade.find(getKey(value));
        }

        java.lang.Integer getKey(String value) {
            java.lang.Integer key;
            key = Integer.valueOf(value);
            return key;
        }

        String getStringKey(java.lang.Integer value) {
            StringBuffer sb = new StringBuffer();
            sb.append(value);
            return sb.toString();
        }

        @Override
        public String getAsString(FacesContext facesContext, UIComponent component, Object object) {
            if (object == null) {
                return null;
            }
            if (object instanceof Category) {
                Category o = (Category) object;
                return getStringKey(o.getIdCategory());
            }
            else {
                throw new IllegalArgumentException("object " + object + " is of type " + object.getClass().getName() + "; expected type: " + CategoryController.class.getName());
            }
        }
    }

POJO对象的一部分

...
public class Category implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "idCategory")
    private Integer idCategory;
    ...

    @Override
    public boolean equals(Object object) {
        if (!(object instanceof Category)) {
            return false;
        }
        Category other = (Category) object;
        if ((this.idCategory == null && other.idCategory != null) || (this.idCategory != null && !this.idCategory.equals(other.idCategory))) {
            return false;
        }
        return true;
}

Functon用于创建SelectItem []数组

public static SelectItem[] getSelectItems(List<?> entities, boolean selectOne) {

        int size = entities.size();
        SelectItem[] items;
        int i = 0;
        if (selectOne) {
            items = new SelectItem[size + 1];
            items[0] = new SelectItem("", ResourceBundle.getBundle("/resources/Bundle").getString("Select_item"));
            i++;
        } else {
            items = new SelectItem[size];
        }

        for (Object x : entities) {
            items[i++] = new SelectItem(x, x.toString());
        }
        return items;
    }

Answer 1

问题在于，当用户编辑业务对象时，我没有正确的SelectItems集合。另外，我添加了<f:converter>来显式调用转换器，我在getAsString()（else部分）中进行了一些更改。

感谢您的时间，并希望这篇文章对其他人有用。

SelectMenuOne

public String prepareEditOrganisationActivity() {
        current = (Activity) organisationActivityItems.getRowData();
        Sector sector = current.getCategory().getSector();
        CategoryController categoryBean = JsfUtil.findBean("categoryController", CategoryController.class);
        categorySelection = categoryBean.categoryItemsBySector(sector);

        return "EditActivity";
}

CategoryControllerConverter

...    
    @Override
    public String getAsString(FacesContext facesContext, UIComponent component, Object object) {
        if (object == null) {
            return null;
        }
        if (object instanceof Category) {
            Category o = (Category) object;
            return getStringKey(o.getIdCategory());
        }
        else {
            Category tmp = new Category();
            return getStringKey(tmp.getIdCategory());                
        }
    }

selectOneMenu不渲染/显示值

1 个答案: