Question

这是我的表：

<h:dataTable var="book" value="#{ordersBean.userOrders}"
             binding="#{ordersBean.htmlDataTable}">
    <h:column>
        <f:facet name="header">order ID</f:facet>
        <h:outputText value="#{book[0]}"/>
    </h:column>
    <h:column>
        <f:facet name="header">Book Title</f:facet>
        <h:outputText value="#{book[1]}"/>
    </h:column>
    <h:column>
        <f:facet name="header">Cost</f:facet>
        <h:outputText value="#{book[2]}"/>
    </h:column>
    <h:column>
        <f:facet name="header">Remove Order</f:facet>
        <h:commandButton action="#{ordersBean.deleteOrder}" image="resources/images/del.gif"/>
    </h:column>
</h:dataTable>

我需要获取用户点击其Order ID图标的行Remove Order，然后从DAO删除该订单。

以下是deleteOrder()：

@ManagedBean
@SessionScoped
public class OrdersBean {

private List<Book> userOrders = new ArrayList<Book>();
private HtmlDataTable htmlDataTable;

@Transactional
public void deleteOrder() {
    Book selectedBook = (Book) htmlDataTable.getRowData(); // class cast exception (168)
}

//For populating table
@Transactional
public List<Book> userAllOrders() {
    userOrders = bookDao.getTitleCostQty(String.valueOf(currentUser.getId())).list();
    return userOrders;
}

public HtmlDataTable getHtmlDataTable() {
    return htmlDataTable;
}

public void setHtmlDataTable(HtmlDataTable htmlDataTable) {
    this.htmlDataTable = htmlDataTable;
}
//getter/setters

但是我收到了这个错误：

javax.servlet.ServletException: java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to com.obs.model.Book
    javax.faces.webapp.FacesServlet.service(FacesServlet.java:659)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

javax.faces.el.EvaluationException: java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to com.obs.model.Book
    javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:101)
    com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)

java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to com.obs.model.Book
    com.obs.bean.OrdersBean.deleteOrder(OrdersBean.java:168)

Answer 1

你使用JSF 2.2吗？也许它从2.0开始有效......

所以你可以在commandButton中传递实际的书：

<h:commandButton actionListener="#{ordersBean.deleteOrder(book)}" ... />

并在bean中接收所选书籍作为参数：

public void deleteOrder(Book selectedBook) {
  // ...
}

Answer 2

对于

GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings = new JsonSerializerSettings()
    {
        ContractResolver = new DefaultContractResolver()
        {
            IgnoreSerializableAttribute = true
        }
    };

，

value="#{ordersBean.userOrders}"应该是DataModel类型，包括模型类型的WrappedData以避免强制转换异常。请执行以下操作：

h:dataTable

现在，它不会通过任何强制转换异常：

private DataModel userOrders = new ListDataModel();

public DataModel getUserOrders() {
    userOrders =  new ListDataModel();
    /* populate your list of Book in another list and setWrappedData for userOrders. */
    List<Book> bookList = userAllOrders();
    if (bookList != null && bookList.size() > 0){
        userOrders.setWrappedData(bookList);
    }   
    return bookList;
}

public void setUserOrders(DataModel userOrders) {
    this.userOrders = userOrders;
}

在jsf datatable中选择一行

2 个答案: