viewParam事件出错 [英] viewParam event going wrong
问题描述
我创建了一个网页，该网页从URL检查视图参数，并调用bean的init方法来检索该用户.然后，该页面上的字段将填充该用户的信息.
I created a webpage, which checks the view-parameter from the URL, and calls the init-method of a bean to retrieve that user. The fields on that page are then filled with the information of that user.
但是出了点问题.
我的Facelets页面:
My Facelets page:
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:f="http://java.sun.com/jsf/core">
<h:head>
<title>Tweetpage of #{userBean.getName()}</title>
</h:head>
<h:body>
<f:metadata>
<f:viewParam name="user" value="#{userBean.name}" />
<f:event type="preRenderView" listener="#{userBean.init}" />
</f:metadata>
<h:commandButton value="Login" action="#{loginBean.login()}" id="login" />
<div class="namebox">
<label>User: #{userBean.name} </label> <br/>
<br/>
</div>
</h:body>
</html>
还有UserBean.java:
And the UserBean.java:
package beans;
import ...
@Named
@RequestScoped
public class UserBean implements Serializable {
private String userName;
private String name;
private String bio;
private String web;
private Collection<Tweet> tweets;
private Collection<User> followers;
private User user;
@Inject
private @Named(value = "kwetterService")
KwetterService service;
@PostConstruct
public void init(ComponentSystemEvent event) throws AbortProcessingException {
System.out.println(name);
user = service.find(name);
if (user != null)
{
name = user.getName();
bio = user.getBio();
web = user.getWeb();
tweets = user.getTweets();
followers = user.getFollowing();
}
}
}
由于未调用System.out.println(name)，因此我不认为该网页正在调用init.如果我在没有URL适应(http://localhost:8080/KwetterJSF/)的情况下启动网页，则会收到以下错误消息:
Since the System.out.println(name) isn't called, I don't think the webpage is calling the init. If I start the webpage without URL-adaptions (http://localhost:8080/KwetterJSF/), I get the following error message:
WELD-000049无法调用[方法] @PostConstruct public beans.UserBean@3c836d3d上的beans.UserBean.init(ComponentSystemEvent)
WELD-000049 Unable to invoke [method] @PostConstruct public beans.UserBean.init(ComponentSystemEvent) on beans.UserBean@3c836d3d
如果我添加参数(http://localhost:8080/KwetterJSF/index.xhtml?user=Sjaak)，则会得到以下信息:
And if I add parameters (http://localhost:8080/KwetterJSF/index.xhtml?user=Sjaak), I get the following:
User: #{userBean.name}
我对此不太有经验，即使我自己做了一点研究也无法弄清楚.有人知道解决方案吗?
I'm not too experienced with this, and I can't figure it out even though I researched a bit myself. Does anybody know the solution?
推荐答案
有2个问题.
首先，您将<f:event>与@PostConstruct混合.
@PostConstruct只能是不接受参数的方法.这就解释了例外.摆脱该注释.无论如何，当视图参数起作用时，它运行得还为时过早.
The @PostConstruct can only be a method which does not take arguments. That explains the exception. Get rid of that annotation. It runs too early anyway when view parameters play a role.
第二，为了正确执行JSF页面，您需要确保浏览器地址栏中显示的URL模式与在/WEB-INF/web.xml中注册的FacesServlet之一匹配.因此，如果是例如*.jsf，则需要确保通过/page.jsf URL(而不是/page.xhtml)打开页面.如果不这样做，JSF标记/组件和EL表达式将不会被识别，因此将被视为纯文本".
Second, in order to properly execute a JSF page, you need to make sure that the URL pattern as appears in browser's address bar matches the one of the FacesServlet as registered in /WEB-INF/web.xml. So if it's for example *.jsf, then you need to make sure that you open the page by /page.jsf URL, not /page.xhtml. If you don't do that, JSF tags/components and EL expressions won't be recognized and thus be treated as "plain text".
更好的方法是直接将FacesServlet映射到*.xhtml的URL模式上.这使您免于虚拟URL的困扰.
Much better is however to just map the FacesServlet directly on an URL pattern of *.xhtml. This saves you from virtual URL headache.
这篇关于viewParam事件出错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！
