使用commandLink从datatable导航时，目标页面上的参数为null

Question

在数据表上，我单击commandLink，该链接导航到目标页面。我需要在该目标网页上获取参数（＆＃39; id＆＃39;在本例中为）。

链接可以正常工作，但不能使用commandLink。我将参数设为null。我必须使用commandLink解决这个问题。

源页面

<p:dataTable value="#{orderBean.orders}" var="order" id="orderDTable" rowKey="#{order.id}">

    <p:column id="editButtonsId" >
        <p:commandLink value="Edit" action="orderInsert" >
            <f:param name="id" value="#{order.id}"/>
        </p:commandLink>

        <!-- works fine with this link -->
        <p:link value="Edit" outcome="orderInsert" >
            <f:param name="id" value="#{order.id}" />
        </p:link>
    </p:column> 

</p:dataTable>

目标网页

<ui:composition template="templates/layout.xhtml"
                xmlns="http://www.w3.org/1999/xhtml"
                xmlns:h="http://java.sun.com/jsf/html"
                xmlns:f="http://java.sun.com/jsf/core"
                xmlns:ui="http://java.sun.com/jsf/facelets"
                xmlns:components="http://java.sun.com/jsf/composite/components"
                xmlns:fn="http://java.sun.com/jsp/jstl/functions"
                xmlns:p="http://primefaces.org/ui">
<f:metadata>
        <f:viewParam name="id" value="#{orderInsertBean.id}" />
        <f:event listener="#{orderInsertBean.init}" type="preRenderView" />
</f:metadata>

</ui:composition>

@Component("orderInsertBean")
@ManagedBean
@RequestScoped
public class OrderInsertBean implements Serializable {

    private String id;

    public void init() {
        // the parameter id is null here when the page is navigated by the commandLink
        FacesMessage msg = new FacesMessage(id, null);
        FacesContext.getCurrentInstance().addMessage(null, msg);
    }

    public String getId() { return id; }
    public void setId(String id) { this.id = id; }
}

Answer 1

首先看这些帖子

• Semantics of "?faces-redirect=true" in <commandlink action=...> and why not use it everywhere

• f:param does not work with p:commandLink or h:commandLink on query string

使用commandLink，您可以使用显示here的@ManagedProperty注释ID，也可以使用请求参数map：

public void init() {
    FacesContext context = FacesContext.getCurrentInstance();  
    Map requestParams = context.getExternalContext().getRequestParameterMap();  
    id = (String) requestParams.get("id");
    // the parameter id is null here when the page is navigated by the commandLink
    FacesMessage msg = new FacesMessage(id, null);
    FacesContext.getCurrentInstance().addMessage(null, msg);
}