Select jsf 数据表中的一行

Question

这是我的 table:

<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 Order ID 用户单击其 Remove Order 图标的那一行，然后从 DAO 中删除该订单。

这里是 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

但是我得到这个错误：

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

value="#{ordersBean.userOrders}" for h:dataTable 应该是 DataModel 类型，包括模型类型的 WrappedData 以避免转换异常。按如下操作：

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;
}

现在，这里不会通过任何转换异常：

Book selectedBook = (Book) htmlDataTable.getRowData();

Answer 2

您使用 JSF 2.2 吗？也许它从 2.0 开始有效 ...

所以你可以在你的 commandButton 中传递实际的书：

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

并在您的 bean 中接收所选书籍作为参数：

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

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