@PostConstruct中的CDI参数 [英] CDI params in @PostConstruct
问题描述
我认为我的问题类似于此但尚未发现它起作用
I think my question is similar to this but haven't found it to work
<f:metadata>
<f:viewParam id="id" name="id" value="#{detailsBean.id}"/>
</f:metadata>
为什么我不能用@Named执行此操作并使用CDI：
Why can't I do this with @Named and utilize CDI:
@Named
@RequestScoped
public class DetailsBean {
private Contacts detailsContact;
@EJB
ContactsFacade contactsEJB;
private int id;
public DetailsBean() {
System.out.println("details bean called");
}
@PostConstruct
public void onLoad() {
detailsContact = contactsEJB.find(id);
}
我无法记录身份。
当然，@ ManagedProperty与CDI不兼容。
Of course, @ManagedProperty is incompatible with CDI.
***** UPDATE *****
*****UPDATE*****
一些xhtml：
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE composition PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<ui:composition xmlns:ui="http://java.sun.com/jsf/facelets"
template="../template.xhtml"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:p="http://primefaces.prime.com.tr/ui"
xmlns:f="http://java.sun.com/jsf/core">
<ui:define name="head">
<f:metadata>
<f:viewParam name="paginator" value="#{contactsBean.contactsTablePaginator}"/>
<f:viewParam name="rows" value="#{contactsBean.contactsTableRows}"/>
</f:metadata>
</ui:define>
<ui:define name="content">
<p:growl id="growl" showDetail="true"/>
<p:panel id="contactsPanel" >
<h:form id ="contactsForm">
<p:dataTable id="contactsTable" value="#{contactsBean.contacts}" selection="#{detailsBean.detailsContact}" var="contacts" widgetVar="contactsTable"
selectionMode="single" rowSelectListener="#{contactsBean.rowSelect}" rowUnselectListener="#{contactsBean.rowUnSelect}"
onRowUnselectUpdate="detailsForm" onRowSelectUpdate="detailsForm"
paginator="#{contactsBean.contactsTablePaginator}" rows="#{contactsBean.contactsTableRows}" rowsPerPageTemplate="5,10,15,25,50,100"
paginatorTemplate="{RowsPerPageDropdown} {FirstPageLink} {PreviousPageLink} {CurrentPageReport} {NextPageLink} {LastPageLink}">
<f:facet name="header">
<p:outputPanel>
<h:outputText value="Search:" />
<p:inputText id="globalFilter" onkeyup="contactsTable.filter()" style="width:150px" />
</p:outputPanel>
</f:facet>
<p:column filterStyle="display:none" filterBy="#{contacts.name}" headerText="Name" style="width:200px">
<h:outputText value="#{contacts.name}" />
</p:column>
<p:column filterStyle="display:none" filterBy="#{contacts.street}" headerText="Street" style="width:280px">
<h:outputText value="#{contacts.street}" />
</p:column>
<p:column filterStyle="display:none" filterBy="#{contacts.city}" headerText="City" style="width:150px">
<h:outputText value="#{contacts.city}" />
</p:column>
<p:column filterStyle="display:none" filterBy="#{contacts.state}" headerText="State" style="width:50px">
<h:outputText value="#{contacts.state}" />
</p:column>
<p:column filterStyle="display:none" filterBy="#{contacts.zip}" headerText="Zip" style="width:100px">
<h:outputText value="#{contacts.zip}" />
</p:column>
<p:column filterStyle="display:none" filterBy="#{contacts.country}" headerText="Country" style="width:150px">
<h:outputText value="#{contacts.country}" />
</p:column>
<p:column filterStyle="display:none" filterBy="#{contacts.sent}" headerText="Sent" style="width:50px">
<h:outputText value="#{contacts.sent}" />
</p:column>
</p:dataTable>
<p:ajaxStatus >
<f:facet name="start">
<h:graphicImage value="../resources/images/ajax-loader-bar.gif" />
</f:facet>
<f:facet name="complete">
<h:graphicImage value="../resources/images/ajax-loader-bar-still.gif" />
</f:facet>
<f:facet name="default">
<h:graphicImage value="../resources/images/ajax-loader-bar-still.gif" />
</f:facet>
</p:ajaxStatus>
<br />
<p:commandLink value="View All" action="#{contactsBean.viewAll}" />
<p:commandLink value="Default View" action="#{contactsBean.viewDefault}" />
<p:commandLink value="Advanced Search" action="search?faces-redirect=true" />
<br />
</h:form>
<br />
</p:panel>
<br />
<br />
<h:form id="detailsForm">
<p:panel id="detailsPanel" visible="#{detailsBean.visible}" >
<h:panelGrid id="detailsPanelGrid" cellpadding="2" cellspacing="2" columns="3" >
<h:outputText value="Name :" />
<p:inputText id="name" value="#{detailsBean.detailsContact.name}" style="width:400px" />
<p:message for="name" />
<h:outputText value="Email :" />
<p:inputText id="email" value="#{detailsBean.detailsContact.email}" style="width:400px" validatorMessage="Must be a valid email address. EX: test@test.com" >
<f:validateRegex pattern="[a-zA-Z0-9]+@[a-zA-Z0-9]+\.[a-zA-Z0-9]+"/>
<p:ajax event="blur" update="emailMsg" />
</p:inputText>
<p:message id="emailMsg" for="email" />
<h:outputText value="Street :" />
<p:inputText id="street" value="#{detailsBean.detailsContact.street}" style="width:400px" />
<p:message for="street" />
<h:outputText value="City :" />
<p:inputText id="city" value="#{detailsBean.detailsContact.city}" style="width:400px" />
<p:message for="city" />
<h:outputText value="State :" />
<p:inputText id="state" value="#{detailsBean.detailsContact.state}" style="width:400px" validatorMessage="Length is greater than 2" >
<f:validateLength maximum="2" />
<p:ajax event="blur" update="stateMsg" />
</p:inputText>
<p:message id="stateMsg" for="state" />
<h:outputText value="Country :" />
<p:inputText id="country" value="#{detailsBean.detailsContact.country}" style="width:400px" />
<p:message for="country" />
<h:outputText value="Phone :" />
<p:inputText id="phone" value="#{detailsBean.detailsContact.phone}" style="width:400px"/>
<p:message for="phone" />
<h:outputText value="Guests :" />
<p:inputText id="guests" value="#{detailsBean.detailsContact.guests}" style="width:400px"/>
<p:message for="guests" />
<h:outputText value="Arrival :" />
<p:calendar id="arrival" value="#{detailsBean.detailsContact.arrival}" showOn="button" />
<p:message for="arrival" />
<h:outputText value="Departure :" />
<p:calendar id="departure" value="#{detailsBean.detailsContact.departure}" showOn="button" />
<p:message for="departure" />
<h:outputText value="Message :" />
<p:inputTextarea id="message" effectDuration="30" style="width:400px;height:100px;" value="#{detailsBean.detailsContact.message}" />
<p:message for="message" />
<h:outputText value="Departure :" />
<p:calendar id="inserted" value="#{detailsBean.detailsContact.inserted}" showOn="button"/>
<p:message for="inserted" />
<h:outputText value="Sent :" />
<h:selectBooleanCheckbox id="sent" value="#{detailsBean.detailsContact.sent}" />
<p:message for="sent" />
<br />
</h:panelGrid>
<p:commandButton value="Submit" action="#{detailsBean.updateContactDetails}" update="contactsForm, growl, stateMsg" />
<p:commandButton value="Close" action="#{detailsBean.handleClose}" update="contactsForm, detailsForm" />
</p:panel>
</h:form>
</ui:define>
</ui:composition>
更多java代码：
package com.atlanticpkg.view.beans;
import com.atlanticpkg.model.entities.Contacts;
import com.atlanticpkg.util.FacesUtils;
import java.io.Serializable;
import javax.annotation.PostConstruct;
import javax.enterprise.context.RequestScoped;
import javax.enterprise.context.SessionScoped;
import javax.inject.Named;
import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import javax.inject.Inject;
@Named(value = "detailsBean")
@RequestScoped
public class EditBean {
private Contacts detailsContact;
private boolean visible = false;
@Inject
ContactsBean contactsBean;
public EditBean() {
}
@PostConstruct
public void onLoad() {
}
public void handleClose() {
this.setVisible(false);
this.setDetailsContact(new Contacts());
}
public void updateContactDetails() {
try {
contactsBean.getContactsEJB().edit(detailsContact);
FacesUtils.addMessage(detailsContact.getName() + " was updated successfully!");
} catch (Exception e) {
FacesContext.getCurrentInstance().addMessage(null, new FacesMessage(FacesMessage.SEVERITY_ERROR, "ERROR", e.toString()));
}
}
}
甚至更多：
@Named(value = "contactsBean")
@RequestScoped
public class ContactsBean {
@Inject
EditBean editBean;
@EJB
private ContactsFacade contactsEJB;
private List<Contacts> contacts = new ArrayList<Contacts>();
private boolean contactsTablePaginator = true;
private int contactsTableRows = 10;
private Contacts selectedContact = new Contacts();
public ContactsBean() {
}
@PostConstruct
public void onLoad() {
updateContactsList();
}
public String viewDefault() {
contactsTablePaginator = true;
contactsTableRows = 10;
return "index?faces-redirect=true&includeViewParams=true";
}
public String viewAll() {
contactsTablePaginator = false;
contactsTableRows = 100;
return "index?faces-redirect=true&includeViewParams=true";
}
public void updateContactsList() {
contacts.clear();
contacts = contactsEJB.findAll();
}
public void rowSelect(SelectEvent event) {
editBean.setVisible(true);
editBean.setDetailsContact((Contacts) event.getObject());
}
public void rowUnSelect(UnselectEvent event) {
editBean.setVisible(false);
editBean.setDetailsContact(new Contacts());
}
}
inputText框填充正常。但是当我点击提交时，它表示值为空。此代码与SessionScope完美配合。
The inputText boxes populate fine. But soon as I hit submit it says that the values are null. This code works perfectly with SessionScope.
警告：/admin/index.xhtml @ 104,109 value =＃{detailsBean.detailsContact.name}：目标无法访问，'null '返回null
javax.el.PropertyNotFoundException：/admin/index.xhtml @ 104,109 value =＃{detailsBean.detailsContact.name}：目标无法访问，'null'返回null
WARNING: /admin/index.xhtml @104,109 value="#{detailsBean.detailsContact.name}": Target Unreachable, 'null' returned null javax.el.PropertyNotFoundException: /admin/index.xhtml @104,109 value="#{detailsBean.detailsContact.name}": Target Unreachable, 'null' returned null
我可以看到它在选择数据表时调用EditBean。然后单击提交按钮时再次调用它。
I can see that it's calling the EditBean when I select the data table. It then calls it again when I click the submit button.
推荐答案
生命周期不允许你的方法。
The lifecycle doesn't allow your approach.
首先，创建bean（构造函数）。之后，执行依赖注入，然后是 @PostConstruct 方法，然后评估JSF文件。并且 viewParam 位于该文件中。因此，您必须注册另一个在填充视图参数后调用的侦听器。
At first, the bean is created ( constructor ). After that, there is executed dependency injection which is followed by @PostConstruct method and after that the JSF file is evaluated. And the viewParam is in that file. So you have to register another listener which is called after filling view params.
我有 @RequestScope bean的解决方案，但如果bean的范围更长（如View）那么这个方法在每个请求（包括AJAX）之后执行，这可能是不可取的。
I have a solution for @RequestScope beans, but if the bean's scope is longer ( like View ) then this method is executed after each request ( including AJAX ) which is not probably desired.
将此用于请求范围bean：
Use this for request scope beans:
<f:metadata>
<f:viewParam id="id" name="id" value="#{detailsBean.id}"/>
<f:event type="preRenderView" listener="#{detailsBean.onLoad}" />
</f:metadata>
对于 @ViewScope bean我正在使用这个hack哪个有效但可能不是最佳实践。它做同样的事情，但可能不是正确的方法。
For @ViewScope beans I am using this "hack" which works but probably is not best practise. It does same thing but probably it isn't the correct approach.
#{detailsBean.onLoad()}
<f:metadata>
<f:viewParam id="id" name="id" value="#{detailsBean.id}"/>
</f:metadata>
我希望这对你有所帮助。
I hope that this is helpful for you.
编辑：
您在这里使用了大量的AJAX。此调用必须至少落在 ViewScoped bean中。查看范围类似于 RequestScope ，但需要相当长的时间 - 直到页面保留为止。
you are using a lot of AJAX here. This calls have to land in at least ViewScoped beans. View Scope is similar to RequestScope, but it takes a quite longer - til the page is left.
但是我没有读过这一切，有很多代码，如果ViewScope没有帮助那么也许你应该提供一小段有问题的代码，以便有机会找到并专注于真正的问题。
But I haven't read it all, there is a lot of code and if the ViewScope doesn't help then maybe you should provide the small piece of problematic code to be chance there to find and focus on the real problem.
这篇关于@PostConstruct中的CDI参数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！
