在jsf datatable中選擇一行

Question

這是我的表：

<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>

我需要獲取用戶點擊它的Remove Order圖標的行的Order ID ，然后從DAO刪除該訂單。

這是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

但我得到這個錯誤：

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嗎？ 也許它從2.0開始有效......

所以你可以在commandButton中傳遞實際的書：

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

並在bean中接收所選書籍作為參數：

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

Answer 2

對於h:dataTable value="#{ordersBean.userOrders}" h:dataTable應該是DataModel類型，包括模型類型的WrappedData以避免強制轉換異常。 請執行以下操作：

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;
}

現在，這里不會通過任何強制轉換異常：

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