将@ManagedBean切换为@Named之后:javax.el.PropertyNotFoundException:无法到达目标，标识符"person"解析为null [英] After switching @ManagedBean to @Named: javax.el.PropertyNotFoundException: Target Unreachable, identifier 'person' resolved to null
问题描述
我只是测试这个JSF页面，所以我没有在<h:commandButton/>中设置action属性.这是一个非常简单的表单，带有3个用于输入名字，姓氏和电子邮件的输入框，以及一个名为保存"的按钮.每次单击该按钮，都会收到此错误
I am just testing out this JSF page, so I don't set the action attribute in the <h:commandButton/>. This is a very simple form with 3 input boxes for First Name, Last Name, and Email, and one button called Save. Every time I click that button, I receive this error
javax.el.PropertyNotFoundException: /index.xhtml @19,106 value="#{person.firstName}": Target Unreachable, identifier 'person' resolved to null
但是如果我对JavaBean @ManagedBean进行注释，那么表单就可以顺利通过，但是每次我切换回使用@Named Bean时，我都会再次收到该错误.我尝试了一些在此站点上找到的建议，例如重新启动服务器，检查吸气剂的存在，但这些建议没有帮助.
but if I annotate my JavaBean @ManagedBean, then the form go through just fine, but every time I switch back to using @Named Bean, I receive that error again. I have tried some of the suggestions I found on this site such as restarting the server, checking the presence of the getters, but those did not help.
<?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:f="http://java.sun.com/jsf/core">
<h:head>
<meta charset="UTF-8" />
<title>Simple Form Created Using Facelets</title>
</h:head>
<h:body>
<h:messages/>
<h:form>
<h:panelGrid columns="2" columnClasses="rightColumn, leftColumn">
<h:outputLabel for="firstName" value="First Name:" />
<h:inputText id="firstName" value="#{person.firstName}"
label="First Name"/>
<h:outputLabel for="lastName" value="Last Name:" />
<h:inputText id="lastName" value="#{person.lastName}" label="Last Name"/>
<h:outputLabel for="email" value="Email:"/>
<h:inputText id="email" value="#{person.email}" label="Email" />
<h:panelGroup />
<h:commandButton value="Submit"/>
</h:panelGrid>
</h:form>
</h:body>
</html>
这是我的JavaBean类
This is my JavaBean class
import javax.annotation.PostConstruct;
import javax.faces.bean.RequestScoped;
import javax.inject.Named;
@Named
@RequestScoped
public class Person {
private String firstName = "empty";
private String lastName = "empty";
private String email = "empty";
public void Person() {}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
这是web.xml文件.
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
<context-param>
<param-name>javax.faces.PROJECT_STAGE</param-name>
<param-value>Development</param-value>
</context-param>
<servlet>
<servlet-name>Faces Servlet</servlet-name>
<servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Faces Servlet</servlet-name>
<url-pattern>/faces/*</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>
30
</session-timeout>
</session-config>
<welcome-file-list>
<welcome-file>faces/index.xhtml</welcome-file>
</welcome-file-list>
</web-app>
推荐答案
This is the best answer to my problem LINK . Also, cdi-1.2 jar file is not available in GS 4.1 for some reason, that is why the package javax.enterprise.* was not present in my Netbeans, I had to manually download that jar from http://cdi-spec.org/. Now everything works fine including DI. And I did not have to create any configuration files to get it to work either.
这篇关于将@ManagedBean切换为@Named之后:javax.el.PropertyNotFoundException:无法到达目标，标识符"person"解析为null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！
