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 biz break; } 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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