Jsf 2 从视图范围bean自动实例化会话范围bean
每次我尝试将会话范围的bean注入到视图范围的bean中时,调用所述bean时都会得到一个NullPointerException。这个问题与 以下是我迄今为止所做的尝试: faces-config.xmlJsf 2 从视图范围bean自动实例化会话范围bean,jsf-2,weblogic-10.x,Jsf 2,Weblogic 10.x,每次我尝试将会话范围的bean注入到视图范围的bean中时,调用所述bean时都会得到一个NullPointerException。这个问题与 以下是我迄今为止所做的尝试: faces-config.xml <managed-bean> <managed-bean-name>sessionBean</managed-bean-name> <managed-bean-class>com.example.SessionBean</
<managed-bean>
<managed-bean-name>sessionBean</managed-bean-name>
<managed-bean-class>com.example.SessionBean</managed-bean-class>
<managed-bean-scope>session</managed-bean-scope>
</managed-bean>
<managed-bean>
<managed-bean-name>viewBean</managed-bean-name>
<managed-bean-class>com.example.ViewBean</managed-bean-class>
<managed-bean-scope>view</managed-bean-scope>
<managed-property>
<property-name>sessionBean</property-name>
<property-class>com.example.SessionBean</property-class>
<value>#{sessionMBean}</value>
</managed-property>
</managed-bean>
ViewBean.java:
package com.example;
public class SessionBean {
public SessionBean() {
System.out.println("Session is instantiated.");
}
public void sayHello() {
System.out.println("Hello from session");
}
}
package com.example;
public class ViewBean {
private SessionBean sessionBean;
private String text = "Look at me!";
public ViewBean() {
System.out.println("View bean is instantiated.");
sessionBean.sayHello();
}
public SessionBean getSessionBean() {
return sessionBean;
}
public void setSessionBean(SessionBean sessionBean) {
this.sessionBean = sessionBean;
}
public String getText() {
return text;
}
}
以及index.xhtml的相关内容:
<f:view>
<h:outputText value="#{viewBean.text}"/>
</f:view>
它在weblogic-10.3.6上运行(或者说不运行),附带了部署为库的jsf-2-0.war
我做错了什么?我希望这不是一个容器bug…您无法访问
@ViewScoped
构造函数中的@SessionScoped
bean。调用@ViewScoped
bean的构造函数后,将设置@SessionScoped
bean。
在某种init方法中使用@PostConstruct
注释来访问@SessionScoped
bean
public ViewBean() {
System.out.println("Constructor viewbean");
}
@PostConstruct
public void init() {
sessionBean.sayHello();
}
更多链接:非常感谢,这当然有道理。您无法注入尚未创建的内容。请尝试用简单的Java术语思考:在
viewBean.setSessionBean(sessionBean)
之前,如何才能执行viewBean=newviewBean()
?
public ViewBean() {
System.out.println("Constructor viewbean");
}
@PostConstruct
public void init() {
sessionBean.sayHello();
}