Remoting and web services using Spring

Spring features integration classes for remoting support using various technologies. The remoting support eases the development of remote-enabled services, implemented by your usual (Spring) POJOs. Currently, Spring supports the following remoting technologies:

• Remote Method Invocation(RMI). Through the use of the RmiProxyFactoryBean and the RmiServiceExporter Spring supports both traditional RMI (with java.rmi.Remote interfaces and java.rmi.RemoteException) and transparent remoting via RMI invokers (with any Java interface).
• Spring’s HTTP invoker. Spring provides a special remoting strategy which allows for Java serialization via HTTP, supporting any Java interface (just like the RMI invoker). The corresponding support classes are HttpInvokerProxyFactoryBean and HttpInvokerServiceExporter.
• Hessian. By using Spring’s HessianProxyFactoryBean and the HessianServiceExporter you can transparently expose your services using the lightweight binary HTTP-based protocol provided by Caucho.
• Burlap. Burlap is Caucho’s XML-based alternative to Hessian. Spring provides support classes such as BurlapProxyFactoryBean and BurlapServiceExporter.
• JAX-WS. Spring provides remoting support for web services via JAX-WS (the successor of JAX-RPC, as introduced in Java EE 5 and Java 6).
• JMS. Remoting using JMS as the underlying protocol is supported via the JmsInvokerServiceExporter and JmsInvokerProxyFactoryBean classes.
• AMQP. Remoting using AMQP as the underlying protocol is supported by the Spring AMQP project

Exposing services using RMI

Link

Exporting the service using the RmiServiceExporter

Of course, we first have to set up our service in the Spring container:

<bean id="accountService" class="example.AccountServiceImpl">
    <!-- any additional properties, maybe a DAO? -->
</bean>

Next we’ll have to expose our service using the RmiServiceExporter:

<bean class="org.springframework.remoting.rmi.RmiServiceExporter">
    <!-- does not necessarily have to be the same name as the bean to be exported -->
    <property name="serviceName" value="AccountService"/>
    <property name="service" ref="accountService"/>
    <property name="serviceInterface" value="example.AccountService"/>
    <!-- defaults to 1099 -->
    <property name="registryPort" value="1199"/>
</bean>

Linking in the service at the client

public class SimpleObject {

    private AccountService accountService;

    public void setAccountService(AccountService accountService) {
        this.accountService = accountService;
    }

    // additional methods using the accountService

}

<bean class="example.SimpleObject">
    <property name="accountService" ref="accountService"/>
</bean>

<bean id="accountService" class="org.springframework.remoting.rmi.RmiProxyFactoryBean">
    <property name="serviceUrl" value="rmi://HOST:1199/AccountService"/>
    <property name="serviceInterface" value="example.AccountService"/>
</bean>

Using Hessian or Burlap to remotely call services via HTTP

Hessian offers a binary HTTP-based remoting protocol. It is developed by Caucho and more information about Hessian itself can be found at http://www.caucho.com.

Link