JSF通过Bean来查看失败 [英] JSF Passing Bean to View Failing

问题描述

我正在尝试编写一个简单的JSF页面，该页面最初包含两个子视图/包含，并将支持bean传递给其中一个包含，因为包含是可重用的(并且在较大的应用程序中可能包含多次)

I am trying to write a simple JSF page that initially includes two subviews/includes, and pass the backing bean to one of the includes because the include is meant to be reusable (and possibly included more than once in a larger application).

这是相关代码:

page1.xhtml

page1.xhtml

<ui:composition xmlns="http://www.w3.org/1999/xhtml"
    xmlns:h="http://xmlns.jcp.org/jsf/html"
    xmlns:p="http://xmlns.jcp.org/jsf/passthrough"
    xmlns:ui="http://xmlns.jcp.org/jsf/facelets"
    xmlns:f="http://xmlns.jcp.org/jsf/core"
    xmlns:pf="http://primefaces.org/ui"
    xmlns:c="http://java.sun.com/jsp/jstl/core"
    template="templates/template1.xhtml">

    <ui:define name="subheader">
        Person Details
    </ui:define>

    <ui:define name="bodyContent">
        <h:form>
            <c:forEach items="#{page1Bean.blockNames}" var="blockName">
                <c:choose>
                    <c:when test="#{blockName} eq 'block1'">
                        <ui:include src="block1.xhtml" >
                            <ui:param name="bean" value="#{page1Bean.myBean}"/>
                        </ui:include>
                    </c:when>
                    <c:otherwise>
                        <ui:include src="#{blockName}.xhtml" />
                    </c:otherwise>
                </c:choose>
            </c:forEach>
            <pf:commandButton value="Ajax Button" action="#{page1Bean.ajaxSubmit()}"/>
        </h:form>

    </ui:define>
</ui:composition>

block1.xhtml

block1.xhtml

<ui:composition 
    xmlns="http://www.w3.org/1999/xhtml"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:p="http://xmlns.jcp.org/jsf/passthrough"
    xmlns:pf="http://primefaces.org/ui">

    <h3>This is the first block</h3>
    <h:panelGrid columns="3" style="margin-bottom:10px" cellpadding="5">

        <pf:outputLabel for="firstName" value="Nombre:" />
        <pf:inputText id="firstName" value="#{bean.firstName}" />
        <h:message id="firstNameMessage" for="firstName" />

    </h:panelGrid>
</ui:composition>

Page1Bean.java

Page1Bean.java

package com.views.prototype;

import java.util.ArrayList;
import java.util.List;
import javax.faces.bean.ManagedBean;
import javax.faces.context.FacesContext;

@ManagedBean
public class Page1Bean {

    private List<String> blockNames;

    private Block1Bean myBean;

    public Page1Bean() {
        blockNames = new ArrayList<String>();

        blockNames.add("block2");
        blockNames.add("block1");

        myBean = new Block1Bean();
    }

    public void ajaxSubmit() {
    }

    @SuppressWarnings("unchecked")
    public static <T> T findBean(String beanName) {
        FacesContext context = FacesContext.getCurrentInstance();
        return (T) context.getApplication().evaluateExpressionGet(context, "#{" + beanName + "}", Object.class);
    }

    public List<String> getBlockNames() {
        return blockNames;
    }

    public void setBlockNames(List<String> blockNames) {
        this.blockNames = blockNames;
    }

    public Block1Bean getMyBean() {
        return myBean;
    }

    public void setMyBean(Block1Bean myBean) {
        this.myBean = myBean;
    }
}

Block1Bean.java

Block1Bean.java

package com.views.prototype;

import javax.faces.bean.ManagedBean;

@ManagedBean
public class Block1Bean {
    private String firstName;

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    @Override
    public String toString() {
        return "Block1Bean [firstName=" + firstName + "]";
    }   
}

页面显示正常，但是当我单击提交"时，我得到:

The page renders ok but when I click submit I get:

value =#{bean.firstName}":无法到达目标，标识符"bean"解析为空

value="#{bean.firstName}": Target Unreachable, identifier 'bean' resolved to null

据我所知，我使用的语法与这些示例的解决方案相同:

As far as I can see I am using the same syntax as the solutions to these examples:

多次重复使用同一页面

将支持bean作为参数传递到Facelet包含

关于我要去哪里的任何想法吗?

Any ideas on where I am going wrong?

推荐答案

问题似乎是JSTL和JSF之间的冲突，如以下几个线程所述:

The problem turns out to be the clash between JSTL and JSF, as noted on several threads:

JSTL c:选择c:when在JSF页面中无法使用

指定< ui内的元素的条件渲染:repeat> ;? < c:if>似乎不起作用

因此，我重写了不使用JSTL的循环，它摆脱了原始问题中的紧迫问题:

So I've rewritten the loop not to use JSTL and it gets rid of the immediate problem in the original question:

        <ui:repeat var="blockName" value="#{page1Bean.blockNames}" varStatus="status">
            <ui:fragment rendered="#{blockName == 'block1'}">
                <ui:include src="#{page1Bean.theBlockName}" >
                    <ui:param name="bean" value="#{page1Bean.myBean}"/>
                </ui:include>
            </ui:fragment>

            <ui:fragment rendered="#{blockName != 'block1' }">
                <ui:include src="block2.xhtml" />
            </ui:fragment>

        </ui:repeat>

(这在功能上不等同于已损坏的目的，但要点是它不使用JSTL).

(This isn't functionally equivalent to the intended purpose of the broken one however the point is it doesn't use JSTL).

这篇关于JSF通过Bean来查看失败的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！