JSF ManagedProperty NullPointerException

时间:2017-08-24 11:01:26

标签: jsf managed-property

我的JSF 2.2项目中有一个sessionScoped ManagedBean,我想调用另一个ManagedBean作为@ManagedProperty这是我的第一个sessionScoped bean:

public class MainWorkerMB implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;


    @ManagedProperty("#{fragmentHandlerMB}")
    private FragmentHandlerMB fragmentHandlerMB;

    public FragmentHandlerMB getFragmentHandlerMB() {
        return fragmentHandlerMB;
    }

    public void setFragmentHandlerMB(FragmentHandlerMB fragmentHandlerMB) {
        this.fragmentHandlerMB = fragmentHandlerMB;
    }

    public void search() {

        fragmentHandlerMB.changeFrag("search_result.xhtml" , "Result Page" , -1);

    }

这是我的另一个bean,它也是sessionScoped

@ManagedBean(eager=true)
@SessionScoped
public class FragmentHandlerMB implements Serializable {

@PostConstruct
    public void init() {
        log.info("constructed..");
        // other code parts //

    }

    public FragmentHandlerMB() {
        super();
    }

public void changeFrag(String fragToOpen, String fragToOpenName, int pageIndex) {

//...

}
}

之后当我尝试调用我的secound bean方法时,我得到了NullPointerException

Caused By: java.lang.NullPointerException
    at com.kebodev.managed.MainWorkerMB.search(MainWorkerMB.java:29)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    Truncated. see log file for complete stacktrace

所以看起来我的豆子不存在。

你能帮帮我吗? 谢谢!

1 个答案:

答案 0 :(得分:1)

我通过移除<managed-bean>中的整个faces-config.xml配置并将@ManagedBean @SessionScoped anotation添加到ManagedBean.

中解决了问题