Passing data between managed components in JSF

Question

Is it actually possible to pass any data between managed components in JSF? If yes, how to achieve this?

Could anyone provide any sample?

Cheyney

Answer 1

There are several ways. If the managed beans are related to each other, cleanest way would be injection. There are different ways depending on JSF version and whether beans are managed by CDI.

CDI

Just use @Inject.

@Named
@SessionScoped
public class Bean1 {

    // ...
}

@Named
@RequestScoped
public class Bean2 {

    @Inject
    private Bean1 bean1; // No getter/setter needed.
}

Other way around can also, the scope of the source and target bean doesn't matter because CDI injects under the covers a proxy.

JSF 2.x

Use @ManagedProperty.

@ManagedBean
@SessionScoped
public class Bean1 {

    // ...
}

@ManagedBean
@RequestScoped
public class Bean2 {

    @ManagedProperty("#{bean1}")
    private Bean1 bean1; // Getter/setter required.
}

Other way around is not possible in this specific example because JSF injects the physical instance and not a proxy instance. You can only inject a bean of the same or broader scope into a bean of a particular scope.

JSF 1.x

Use <managed-property> in faces-config.xml.

public class Bean1 {

    // ...
}

public class Bean2 {

    private Bean1 bean1; // Getter/setter required.
}

<managed-bean>
    <managed-bean-name>bean1</managed-bean-name>
    <managed-bean-class>com.example.Bean1</managed-bean-class>
    <managed-bean-scope>session</managed-bean-scope>
</managed-bean>

<managed-bean>
    <managed-bean-name>bean2</managed-bean-name>
    <managed-bean-class>com.example.Bean2</managed-bean-class>
    <managed-bean-scope>request</managed-bean-scope>
    <managed-property>
        <property-name>bean1</property-name>
        <value>#{bean1}</value>
    </managed-property>
</managed-bean>

See also:

• Backing beans (@ManagedBean) or CDI Beans (@Named)?
• How to choose the right bean scope?
• Get JSF managed bean by name in any Servlet related class

Iaria

Answer 2

To add to BalusC's answer, if you are using a dependency-injection framework (spring, guice, etc.), or if using JSF 2.0, you can have one managed bean set into the other using just:

@Inject
private Bean2 bean2;

(or the appropriate annotation based on your DI framework)

Odawa

Should be @Inject private Bean1 bean1; if this were to be referenced in Bean2. (in sync with BalusC's example) – Halfmoon