Java EE 6：目标不可达，标识符“helloBean”解析为空
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Java EE 6: Target Unreachable, identifier 'helloBean' resolved to null
提问by Lou Rous
I am trying to get a simple JSF 2 tutorial example to work.
我正在尝试使用一个简单的 JSF 2 教程示例。
I am using the dynamic web project in Eclipse and publishing to a Glassfish 3 server (run -> run on server). The first index.xhtml page loads correctly, but when I have to access a managed bean, the following error displays:
我在 Eclipse 中使用动态 Web 项目并发布到 Glassfish 3 服务器（运行 -> 在服务器上运行）。第一个 index.xhtml 页面正确加载，但是当我必须访问托管 bean 时，显示以下错误：
/index.xhtml @14,48 value="#{helloBean.name}": Target Unreachable, identifier 'helloBean' resolved to null
I've had a look at the various other discussions on this topic, however the solutions never seem to work for me (e.g. adding beans.xml, giving the managed bean a name etc, following naming conventions).
我查看了有关该主题的各种其他讨论，但是这些解决方案似乎对我不起作用（例如，添加 beans.xml、为托管 bean 命名等，遵循命名约定）。
Any help would be appreciated.
任何帮助，将不胜感激。
Here is the code I am currently working with:
这是我目前正在使用的代码：
Index.xhtml
索引.xhtml
<?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:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html">
<h:head>
<title>JSF 2.0 Hello World</title>
</h:head>
<h:body>
<h3>JSF 2.0 Hello World Example - hello.xhtml</h3>
<h:form>
<h:inputText value="#{helloBean.name}"></h:inputText>
<h:commandButton value="Welcome Me" action="response"></h:commandButton>
</h:form>
</h:body>
</html>
response.xhtml:
响应.xhtml：
<?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">
<h:head>
<title>JSF 2.0 Hello World</title>
</h:head>
<h:body bgcolor="white">
<h3>JSF 2.0 Hello World Example - welcome.xhtml</h3>
<h4>Welcome #{helloBean.name}</h4>
</h:body>
</html>
Managed bean:
托管豆：
package java.hello1;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
import java.io.Serializable;
@ManagedBean
@SessionScoped
public class HelloBean implements Serializable {
private static final long serialVersionUID = 1L;
private String name = "Ricardo";
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
web.xml:
网页.xml：
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
id="WebApp_ID" version="2.5">
<display-name>JavaServerFaces</display-name>
<!-- Change to "Production" when you are ready to deploy -->
<context-param>
<param-name>javax.faces.PROJECT_STAGE</param-name>
<param-value>Development</param-value>
</context-param>
<!-- Welcome page -->
<welcome-file-list>
<welcome-file>faces/index.xhtml</welcome-file>
</welcome-file-list>
<!-- JSF mapping -->
<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<!-- Map these files with JSF -->
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>/faces/*</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>*.jsf</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>*.faces</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>*.xhtml</url-pattern>
</servlet-mapping>
</web-app>
回答by BalusC
You need to have a JSF 2.0 compliant /WEB-INF/faces-config.xmlfile in order to get JSF to interpret the annotations.
您需要有一个符合 JSF 2.0 的/WEB-INF/faces-config.xml文件才能让 JSF 解释注释。
<?xml version="1.0" encoding="UTF-8"?>
<faces-config
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-facesconfig_2_0.xsd"
version="2.0">
<!-- Config here. Can even be kept empty. -->
</faces-config>
If you already have one or if that doesn't solve the problem, please pay attention to server startup logs if you don't see any warnings/errors.
如果您已经有一个或如果这不能解决问题，如果您没有看到任何警告/错误，请注意服务器启动日志。
By the way, your /WEB-INF/web.xmlfile is declared conform Servlet 2.5 specification. While this may not necessarily harm, it makes no sense if you're using a Servlet 3.0 compliant container. Update the root declaration as follows:
顺便说一下，您的/WEB-INF/web.xml文件被声明为符合 Servlet 2.5 规范。虽然这不一定有害，但如果您使用的是 Servlet 3.0 兼容容器，则毫无意义。更新根声明如下：
<?xml version="1.0" encoding="UTF-8"?>
<web-app
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
<!-- Config here. -->
</web-app>
The /WEB-INF/beans.xmlis intented for CDI annotations like @Named, @Injectand so on. Just a completely empty file is sufficient to turn it on. It has totally no relationship to JSF annotations like @ManagedBean, @ManagedPropertyand so on. It should also not be confused/mixed with each other.
该/WEB-INF/beans.xml是intented为CDI注解一样@Named，@Inject等等。只需一个完全空的文件就足以将其打开。它有JSF注释完全一样没有关系@ManagedBean，@ManagedProperty等等。它也不应该相互混淆/混合。
回答by alehro
I've been stuck with such a problem for half a day. The problem in my case appears only when I do run the WebApp from Eclipse. JSF 2 looks in WEB-INF/classes for annotated beans and doesn't find them. To solve this I've changed build output path to WebContent/WEB-INF/classes. Here is detailed explanation of similar case: Jetty maven goal jetty:run does not work with JSF 2.0 @ManagedBean
我已经被这个问题困了半天了。我的问题只有在我从 Eclipse 运行 WebApp 时才会出现。JSF 2 在 WEB-INF/classes 中查找带注释的 bean，但没有找到它们。为了解决这个问题，我将构建输出路径更改为 WebContent/WEB-INF/classes。这里是类似案例的详细解释：Jetty maven goal jetty:run does not work with JSF 2.0 @ManagedBean
回答by sendon1982
Please you check your war file and see if your classes are under WEB-INF/classes folder. I ran into the same problem and found out there are no class files WEB-INF/classes folder.
请检查您的 war 文件，看看您的类是否在 WEB-INF/classes 文件夹下。我遇到了同样的问题，发现 WEB-INF/classes 文件夹中没有类文件。
回答by Forge_7
In the exact same scenario as OP (with eclipse, publishing to a Glassfish 3 server using run -> run on server) I get exactly the same error until removing spaces from the eclipse Project Name. Simply removing any spaces solved the problem.
在与 OP 完全相同的场景中（使用 eclipse，使用 run -> run on server 发布到 Glassfish 3 服务器）我得到完全相同的错误，直到从 eclipse 项目名称中删除空格。只需删除任何空格即可解决问题。
回答by Paulo Henrique Alves
Include @Named in your Controller/Bean..
在您的控制器/Bean 中包含 @Named ..
回答by umitkilic
I had the same problem, i tried everything. After that, i just clicked "Click and Build Project" button, "Build Project" button and resarted GlassFish server. After, it works to me, for now :)
我有同样的问题，我尝试了一切。之后，我只需单击“单击并构建项目”按钮、“构建项目”按钮并重新启动 GlassFish 服务器。之后，它对我有用，现在:)
