RMI简单实例

 

主要步骤 
1.创建远程接口及声明远程方法（RmiMonitorService.java） 

package com.rmi.service;import java.rmi.Remote;import java.rmi.RemoteException;/** * Description: 实时显示RMI服务接口. s * RMI接口必须扩展接口java.rmi.Remote * @author Peter Wei * @version 1.0 Feb 25, 2009 */ public interface RmiMonitorService extends Remote{ /** * 实时显示对外接口 * @param funindex 功能号 * @param param 键名列表，也就是实际传输的内容 * @return * @throws RemoteException 远程接口方法必须抛出java.rmi.RemoteException */ public int interactive(int funindex, String param) throws RemoteException; } 

2.实现远程接口及远程方法（继承UnicastRemoteObject）(RmiMonitorServiceImpl.java) 

package com.rmi.service;import java.rmi.RemoteException;import java.rmi.server.UnicastRemoteObject;public class RmiMonitorServiceImpl extends UnicastRemoteObject implements RmiMonitorService {private static final long serialVersionUID = -3771656108378649574L;public static final int SUCCSS = 1;public static final int FAIL = 0;public WarnService warnService;/** * 必须定义构造方法，因为要抛出RemoteException异常 * * @throws RemoteException */public RmiMonitorServiceImpl() throws RemoteException {super();}public int interactive(int funindex, String param) throws RemoteException {int result = FAIL;switch (funindex) {// 告警case (1): {// warnService = (WarnService) AppContext.getAppContext().getBean(// "warn.warnService");// 实际应用是从Spring应用中获取告警Service,如上代码warnService = new WarnServiceImpl();// 网络告警的业务操作warnService.dealWarn(param);result = SUCCSS;}break;case (2):// do other bizbreak;}return result;}public WarnService getWarnService() {return warnService;}public void setWarnService(WarnService warnService) {this.warnService = warnService;}} 

3.启动RMI注册服务，并注册远程对象（RmiServer.java） 

package com.rmi.service;import java.net.MalformedURLException;import java.rmi.AlreadyBoundException;import java.rmi.Naming;import java.rmi.RemoteException;import java.rmi.registry.LocateRegistry;public class RmiServer {public String ip = "localhost"; public int port = 8889; /** * 启动RMI注册服务，并注册远程对象.实际应用中是在Spring初始化并启动 */ public void init() { try { LocateRegistry.createRegistry(port); // 创建一个远程对象 RmiMonitorService comm = new RmiMonitorServiceImpl(); Naming.bind("//" + ip + ":" + port + "/comm", comm); } catch (RemoteException e) { System.out.println("创建远程对象发生异常！" + e.toString()); e.printStackTrace(); } catch (AlreadyBoundException e) { System.out.println("发生重复绑定对象异常！" + e.toString()); e.printStackTrace(); } catch (MalformedURLException e) { System.out.println("发生URL畸形异常！" + e.toString()); e.printStackTrace(); } } public String getIp() { return ip; } public void setIp(String ip) { this.ip = ip; } public int getPort() { return port; } public void setPort(int port) { this.port = port; } public static void main(String[] args) { // 实际应用中是在Spring初始化并启动 RmiServer rmiServer = new RmiServer(); System.out.println("RMI服务初始化:"); rmiServer.init(); }} 

4.客户端查找远程对象，并调用远程方法（MonitorClient.java） 

package com.rmi.service;import java.net.MalformedURLException;import java.rmi.Naming;import java.rmi.NotBoundException;import java.rmi.RemoteException;public class MonitorClient {public RmiMonitorService monitorService; public String ip = "localhost"; public int port = 8889; public int interactive(int funindex, String param) { int result = 0; try { getMonitorService().interactive(funindex, param); result = 1; } catch (RemoteException e) { e.printStackTrace(); } return result; } public RmiMonitorService getMonitorService() { try { // 在RMI服务注册表中查找名称为RmiMonitorService的对象，并调用其上的方法 monitorService = (RmiMonitorService) Naming.lookup("rmi://" + ip + ":" + port + "/comm"); } catch (NotBoundException e) { e.printStackTrace(); } catch (MalformedURLException e) { e.printStackTrace(); } catch (RemoteException e) { e.printStackTrace(); } return monitorService; } public static void main(String args[]) throws RemoteException { MonitorClient client = new MonitorClient(); System.out.println("发送告警信息:"); String msg = "tsid=1022&devid=10001027&warnid=102&warntype=01&warnlevel=1&warnmsg=设备出错,请检查."; System.out.println(client.getValue(msg, "warnmsg")); client.interactive(1, msg); } public String getValue(String content, String key) { String value = ""; int begin = 0, end = 0; begin = content.indexOf(key + "="); end = content.indexOf("&", begin); if (end == -1) end = content.length(); value = content.substring(begin + key.length() + 1, end); return value; } } 

 

 

另外两个辅助类：

1.WarnService.java

package com.rmi.service;public interface WarnService {/** * 处理告警:告警来时的业务操作,实际操作是解析消息存库，然后界面Ajax定时刷新数据，获取实时告警展示 * * @param message * @return */ public int dealWarn(String message); }

 2.WarnServiceImpl .java

package com.rmi.service;public class WarnServiceImpl implements WarnService { public int dealWarn(String message) { // 告警处理方法 System.out.println("已接收网络告警"); // … return 1; } } 

 

 

 

出现的问题：

1、java.rmi.server.ExportException: remote object implements illegal remote interface; nested exception is:

这是由于接口和方面没有抛出异常导致，在每个方法和结构都加上throws RemoteException 就解决了

 

转载：http://www.javaeye.com/topic/744239

 

 

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