spring中实现rmi的一个例子及说明

rmi是java体系中实现分布式计算的重要手段.spring也提供了rmi的远程服务调用,本文主要讨论如何用spring的IOC实现rmi的远程服务调用

首先定义需要使用的域对象(Account), 这是由远端计算以后产生Account的对象,并将该对象传递给客户端:

package rmi;
import java.io.Serializable;

public class Account implements Serializable{
  private String name;
  
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
}

定义远程提供的模拟的服务insertAccount, getAccounts
定义域服务

package rmi;
import java.util.*;

public interface AccountService {
  public void insertAccount(Account account);
  public List getAccounts(String name);
}

实现远程的服务服务(通常情况下需要访问数据库而构造出域对象)

package rmi;

import java.util.List;
import java.util.*;

public class AccountServiceImpl implements AccountService {

  public void insertAccount(Account account) {
    System.out.println(account.getName());

  }

  public List getAccounts(String name) {
    List accountList = new ArrayList();
    Account a = new Account();
    a.setName("kevin");
    accountList.add(a);
    return accountList;
  }

}

定义客户端:
客户端是一个使用AccountService管理账户的简单对象

package rmi;
public class SimpleObject {
  private AccountService accountService;

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

实现客户端

package rmi;

import org.springframework.context.support.ClassPathXmlApplicationContext;
import java.util.*;
public class AccountTest {

  public static void main(String[] args) {
    ClassPathXmlApplicationContext appContext = new ClassPathXmlApplicationContext(
        new String[] { "rmi/rmi.xml" });
    
    SimpleObject so = (SimpleObject)appContext.getBean("simpleService");
    AccountService as = so.getAccountService();
    List accounts = as.getAccounts("kevin");
    Iterator iter = accounts.iterator();
    while(iter.hasNext()){
      Account account = (Account)iter.next();
      System.out.println(account.getName());
    }
  }
}

配置bean之间的关系
配置文件:rmi.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
                 <!--域服务-->
  <bean id="accountService" class="rmi.AccountServiceImpl"/>
  <!--注册域服务-->
  <bean class="org.springframework.remoting.rmi.RmiServiceExporter">
    <property name="serviceName"><value>AccountService</value></property>
    <property name="service"><ref bean="accountService"/></property>
    <property name="serviceInterface">
      <value>rmi.AccountService</value>
    </property>
    <property name="registryPort"><value>1199</value></property>
  </bean>  
  <!--客户端查找域服务的stub-->
  <bean id="simpleService" class="rmi.SimpleObject">
    <property name="accountService"><ref bean="accountServiceClient"/></property>
  </bean>
  
  <bean id="accountServiceClient" class="org.springframework.remoting.rmi.RmiProxyFactoryBean">
    <property name="serviceUrl"><value>rmi://localhost:1199/AccountService</value></property>
    <property name="serviceInterface"><value>rmi.AccountService</value></property>
  </bean>
</beans>