Is a servlet container a prerequisite for running a spring ?

[joergen]

Is it possible to expose remote services without using a servlet/JSP container (for example by using the RMI registry) with spring ?

And, is it possible to create a standalone application without a servlet/JSP container ?

I

[cmgharris]

Yes to both questions.

For example, something like:

public class ServerImpl extends UnicastRemoteObject  implements ServerIface {


    public ServerImpl() throws RemoteException {
    }

    public static void main(String[] args) {
        new ClassPathXmlApplicationContext("ServerContext.xml");
    }
    
    // Remote interface implementation follows here:
}

with a Spring context (ServerContext.xml) looking like:

<beans>
    <bean id="pafService" class="foo.bar.ServerImpl" />

    <bean class="org.springframework.remoting.rmi.RmiServiceExporter">
        <property name="serviceName"><value>pafService</value></property>
        <property name="service"><ref bean="pafService"/></property>
        <property name="serviceInterface"><value>foo.bar.ServerIface</value></property>
        <property name="registryPort"><value>yourRegistryPortNo</value></property>
        <property name="servicePort"><value>yourServicePortNo</value></property>
    </bean>
</beans>

I've tried to cut out extraneous detaiil, but I hope I've got the essentiials there. When you run the main method, your service will be available on the ports you've specified. You don't need to be running a separate registry.
For an ordinary stand alone app, your spring context will be different - you won't have the RmiServiceExporter - and after loading the context, you'll probably want to do a bit more in your main method.
Hope this helps

[joergen]

It does certainly seems to be a remarkebly easy and flexible -
thanks a lot.

[alexis]

I can't understand why this code registers my bean :

new ClassPathXmlApplicationContext("beans.xml");

but this one doesn't :

ClassPathResource res = new ClassPathResource("beans.xml");
XmlBeanFactory factory = new XmlBeanFactory(res);

The fact is I tried the second one first when I read Spring's reference (3.2.1. The BeanFactory).

Here is my beans.xml file

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" 
	"http&#58;//www.springframework.org/dtd/spring-beans.dtd">

<beans>
	<bean id="HelloServer" class="aot.essai.spring.server.HelloServer"/>

	<bean class="org.springframework.remoting.rmi.RmiServiceExporter">
		<property name="serviceName"><value>HelloService</value></property>
		<property name="service"><ref bean="HelloServer"/></property>
		<property name="serviceInterface"><value>aot.essai.spring.Hello</value></property>
		<!-- defaults to 1099 -->
		<property name="registryPort"><value>1199</value></property>
	</bean>
</beans>

Any idea ?

[gpoirier]

The reason is that BeanFactories don't eagerly instanciate singletons, while ApplicationContextes do. When using a BeanFactory, you have to call preInstantiateSingletons() explicitely.

Guillaume