Spring RMI 入门技术

对于一个Java接口来说，如果使用者和其实现类不在同一环境，比如实现类在网络的其他机器，那么如何来访问接口实现类的逻辑呢？答案是远程方法调用。简称RMI。

Spring 简化了RMI的实现过程，我们现在只要配置好即可正确发布我们的RMI服务。

package com.spring.rmi.common;

public interface IPerson {
	
	public String getName();
	
	public String getEmail();
	
}

package com.spring.rmi.common.impl;

import com.spring.rmi.common.IPerson;

public class PersonImpl implements IPerson {

	@Override
	public String getName() {
		return "mike";
	}

	@Override
	public String getEmail() {
		return "[e-mail]";
	}

}

服务端配置文件:server-rmi.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">

	<!-- 1.用RMI发布的接口实现类 -->
	<bean id="personImpl" class="com.spring.rmi.common.impl.PersonImpl" />

	<!-- 2.利用Spring类发布这个RMI服务 -->
	<bean id="service" class="org.springframework.remoting.rmi.RmiServiceExporter">
		<property name="service">
			<!-- 2.1指定服务的实现 -->
			<ref bean="personImpl" />
		</property>
		<property name="serviceName">
			<!-- 2.2指定服务的名字 -->
			<value>person</value>
		</property>
		<property name="serviceInterface">
			<!-- 2.3指定服务的接口 -->
			<value>com.spring.rmi.common.IPerson</value>
		</property>
		<property name="registryPort">
			<!-- 2.4指定服务的端口 -->
			<value>5923</value>
		</property>
	</bean>
</beans>

package com.spring.rmi;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class RmiBootstrap {
	
	public static void main(String[] args) throws InterruptedException {
		new ClassPathXmlApplicationContext("server-rmi.xml");
		Thread.sleep(1000 * 60 * 60 );
	}
	
	
}

这样就启动了我们的RMI服务，那么客户端如果使用呢？


客户端配置文件:client-rmi.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">

	<bean id="person" class="org.springframework.remoting.rmi.RmiProxyFactoryBean">
		<property name="serviceInterface">
			<value>com.spring.rmi.common.IPerson</value>
		</property>
		<property name="serviceUrl">
			<value>rmi://localhost:5923/person</value>
		</property>
	
	</bean>
</beans>

package client;

import org.apache.log4j.Logger;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.spring.rmi.common.IPerson;

public class RmiInvoke {
	private static final Logger logger = Logger.getLogger(RmiInvoke.class);
	public static void main(String[] args) {
		ApplicationContext context = new ClassPathXmlApplicationContext("client-rmi.xml");
		IPerson p = (IPerson) context.getBean("person");
		
		logger.info(p.getName());
		logger.info(p.getEmail());
	}
}

运行结果
etc...
16:55:12 [main] INFO (RmiInvoke.java:15) - mike
16:55:12 [main] INFO (RmiInvoke.java:16) - [e-mail]


以上代码运行还需要必要的jar包
Spring相关jar包
aopalliance.jar
apache commons-logging.jar


在实际使用中还有一种情况是开多个服务

其实只要在服务端多配置一个类似的RmiServiceExporter
当然发布的时候注意名称不要相同即可。