Java 在素数数据表中选择行

Select Row in primefaces data table

提问by

I have this table:

我有这张桌子：

<h:form>
    <p:dataTable id="books" value="#{ordersBean.userOrders}" var="book" selection="#{ordersBean.selectedBook}">
        <p:column>
            <f:facet name="header">Order ID</f:facet>
            <h:outputText value="#{book[0]}"/>
        </p:column>
        <p:column>
            <f:facet name="header">Title</f:facet>
            <h:outputText value="#{book[1]}"/>
        </p:column>
        <p:column>
            <f:facet name="header"></f:facet>
            <p:commandButton id="selectRowBtn" value="select" action="#{ordersBean.showSelectedBook}"/>
        </p:column>
    </p:dataTable>
</h:form>

I want when i click on each selectbutton, it's row information assigned to selectedBookproperty and displays it in showSelectedBook()method:

我想要当我点击每个select按钮时，它是分配给selectedBook属性的行信息并在showSelectedBook()方法中显示它：

Here is the ordersBean:

这是ordersBean：

private Book selectedBook = new Book();

public Book getSelectedBook() {
    return selectedBook;
}

public void setSelectedBook(Book selectedBook) {
    this.selectedBook = selectedBook;
}

public void showSelectedBook() {
    System.out.println("In selected Book(), book: " + getSelectedBook());
}

But result is this:

但结果是这样的：

In selected Book(), book: null

In selected Book(), book: null

采纳答案by cн?dk

If you want to show the selected book you have to set selectionMode="single"and there's no need to put a commandButtonin each row, just specify only one commandButtonin the footer facet like this:

如果您想显示您必须设置的所选书籍selectionMode="single"并且不需要commandButton在每一行中放置一个，只需commandButton在页脚方面仅指定一个，如下所示：

<f:facet name="footer">
        <p:commandButton id="selectRowBtn" value="select" action="#{ordersBean.showSelectedBook}"/>
    </f:facet>

And your main problemhere is that you are setting a new Book()to your selectedBookvariable, so a nullvalue to your selectedBook, this declaration:

您的主要问题是您正在new Book()为selectedBook变量设置 a ，因此null您的值selectedBook，此声明：

private Book selectedBook = new Book();

Should be :

应该 ：

private Book selectedBook;

You don't have to instantiate a new Book()in your selectedBook.

你不必new Book()在你的selectedBook.

Take a look at the second Example in this Showcase, to see how it works.

看看这个Showcase中的第二个例子，看看它是如何工作的。

回答by Parkash Kumar

Should be something like this:

应该是这样的：

XML code:

XML 代码：

<p:commandButton id="selectRowBtn" value="select" 
    action="#{ordersBean.showSelectedBook}">
    <f:param name="bookId" value="#{book[0]}" />
</p:commandButton>

Java bean method:

Java bean 方法：

public void showSelectedBook() {

    Map<String,String> params = 
        FacesContext.getExternalContext().getRequestParameterMap();

    int bookId = Integer.valueOf(params.get("bookId"));

    for(Book book : bookList){
        if(book.bookId == bookId){
            selectedBook = book;
            break;
        }
    }

    System.out.println("In selected Book(), book: " + getSelectedBook());
}

Beside, you must have knowledge about the patterns for sending parameters to the actions, refer below link. http://www.mkyong.com/jsf2/4-ways-to-pass-parameter-from-jsf-page-to-backing-bean/

此外，您必须了解向操作发送参数的模式，请参阅以下链接。 http://www.mkyong.com/jsf2/4-ways-to-pass-parameter-from-jsf-page-to-backing-bean/

回答by Spartan

better solution and without select button :

更好的解决方案并且没有选择按钮：

Xml code:

xml代码：

<p:dataTable id="ListBook"
    value="#{ordersBean.bookList}"
    selection="#{ordersBean.selectedBook}" var="book"
    rowKey="#{book.id}" selectionMode="single">

    <p:ajax event="rowSelect"
        listener="#{ordersBean.onRowSelectDataTable()}"
                                    update="ListBook" />
  ..... <columns> ..
</p:datatable>

Java bean:

爪哇豆：

private Book selectedBook=new Book();
private boolean headerButtonsDisabled=true;
//add a List object for all books (bookList) with getter and setter


public boolean isHeaderButtonsDisabled() {
        return headerButtonsDisabled;
    }

public void setHeaderButtonsDisabled(boolean headerButtonsDisabled) {
    this.headerButtonsDisabled = headerButtonsDisabled;
}

public void onRowSelectDataTable() {
    this.setHeaderButtonsDisabled(false);
}

public Book getSelectedBook() {
        return selectedBook;
    }

public void setSelectedBook(Book selectedBook) {
    this.selectedBook = selectedBook;
}