jsfsession-scopemanaged-property

Can't I access session scope variable using @ManagedProperty?

I know I can put/get session scope variables like this.

FacesContext.getCurrentInstance().getExternalContext()
    .getSessionMap().put(SESSION_KEY_SOME, some);

Then can't I access the value like this?

@ManagedBean
@SessionScoped
public class SomeOtherBean {

    @ManagedProperty("#{sessionScope.some}")
    private Some some;
}

The value is null.

Solution

  • @ManagedProperty runs during creation/instantiation of the @ManagedBean.

    So, when the @ManagedBean is created before the #{sessionScope.some} is set for first time, then it will still remain null in the @ManagedBean. It will only work when @ManagedBean is created after the #{sessionScope.some} is set for the first time.

    There are basically three ways to achieve the desired behavior.

    1. Replace private Some some by externalContext.getSessionMap().get("some").

      @ManagedBean
@SessionScoped
public class SomeOtherBean {

    public void someMethod() {
        Some some = (Some) FacesContext.getCurrentInstance()
            .getExternalContext().getSessionMap().get("some");
        // ...
    }

}

    2. Replace @SessionScoped by @RequestScoped.

      @ManagedBean
@RequestScoped
public class SomeOtherBean {

    @ManagedProperty("#{sessionScope.some}")
    private Some some;

    // ...
}

    3. Replace externalContext.getSessionMap().put("some", some) by directly setting it as bean property.

      @ManagedBean
public class SomeBean {

    @ManagedProperty("#{someOtherBean}")
    private SomeOtherBean someOtherBean;

    public void someMethod() {
        // ...
        someOtherBean.setSome(some);
    }

    // ...
}

    See also: