CORBA

一．题目分析： 充分利用CORBA系统中对象的特点：接口的继承性，操作和属性自身的特点。通过两个实例分析COBRA内部实现结构。 二．配制环境JDK环境： ``

三.具体实现 题目一：Java版CORBA程序1——HelloWorld 1.编写IDL接口HelloWorld.idl module sample{ interface HelloWorld{ wstring sayHello(); }; }; 说明：CORBA处理字符串有：String和wstring两种类型，string类型主要用于处理ASCII类型的字符串，wstring用于处理多字节的字符串 2.编译IDL接口 编译结果生成sample包，生成下述文件 _HelloWorldStub.java HelloWorld.java HelloWorldHelper.java HelloWorldHolder.java HelloWorldOperations.java HelloWorldPOA.java 3.编写并编译服务端程序:HelloWorldServer.java

import sample.*; import org.omg.CosNaming.*; import org.omg.CosNaming.NamingContextPackage.*; import org.omg.CORBA.*; import org.omg.CORBA.portable.*; import org.omg.PortableServer.*; class HelloWorldServant extends HelloWorldPOA{ //对象实现类 public String sayHello(){ return "\nHello World!17408070111孟婷婷\n"; } } public class HelloWorldServer{ //服务程序 public static void main(String args[]){ try{ //初始化ORB ORB orb = ORB.init(args, null); //取根POA的引用 org.omg.CORBA.Object poaobj = orb.resolve_initial_references ("RootPOA"); org.omg.PortableServer.POA rootPOA = org.omg.PortableServer.POAHelper.narrow(poaobj); org.omg.PortableServer.POAManager manager = rootPOA.the_POAManager(); //创建伺服对象 HelloWorldServant objRef = new HelloWorldServant(); HelloWorld obj = objRef._this(orb); //绑定命名服务 NamingContext ncRef = NamingContextHelper.narrow(orb.resolve_initial_references("NameService")); NameComponent nc = new NameComponent("Hello", ""); NameComponent path[] = {nc}; ncRef.rebind(path, obj); //激活POA管理器 manager.activate(); //等待处理客户程序的请求 System.out.println("HelloWorld is running!"); orb.run(); }catch (Exception e) { System.err.println("ERROR: " + e); e.printStackTrace(System.out); } } }

4.编写并编译客户端程序: HelloWorldClient.java

import sample.*; import org.omg.CosNaming.*; import org.omg.CORBA.*; public class HelloWorldClient { public static void main(String args[]) { try{ ORB orb = ORB.init(args, null); org.omg.CORBA.Object objRef = orb.resolve_initial_references("NameService"); NamingContext ncRef = NamingContextHelper.narrow(objRef); NameComponent nc = new NameComponent("Hello",""); NameComponent path[] = {nc}; HelloWorld helloWorld = HelloWorldHelper.narrow(ncRef.resolve(path)); String hello = helloWorld.sayHello(); System.out.println(hello); } catch (Exception e) { System.out.println("ERROR : " + e) ; e.printStackTrace(System.out); } } }

5.运行 （1）启动名字服务器： （2）启动服务端程序：

（3）启动客户端程序：

题目2.JAVA版CORBA程序2——Counter 编写实现连加、连减和加减混合等数学++/- -运算，并进行测试。 1 编写IDL接口counter.idl： module CounterApp{ interface Counter{ readonly attribute long value; void inc(); void dec(); }; }; 2编译IDL接口： 编译结果生成CounterApp包，生成下述文件 _CounterStub.java Counter.java CounterHelper.java CounterHolder.java CounterOperations.java CounterPOA.java 3 编写并编译对象实现代码：CounterImpl.java 4 编写并编译服务端程序: Server.java

import CounterApp.*; import java.io.*; import org.omg.CosNaming.*; import org.omg.CosNaming.NamingContextPackage.*; import org.omg.CORBA.*; import org.omg.CORBA.portable.*; import org.omg.PortableServer.*; public class Server { public static void main(String[] args){ try{ ORB orb = ORB.init(args, null); org.omg.CORBA.Object poaobj = orb.resolve_initial_references ("RootPOA"); org.omg.PortableServer.POA rootPOA = org.omg.PortableServer.POAHelper.narrow(poaobj); org.omg.PortableServer.POAManager manager = rootPOA.the_POAManager(); CounterImpl c_impl = new CounterImpl(); Counter c = c_impl._this(orb); NamingContext ncRef = NamingContextHelper.narrow(orb.resolve_initial_references("NameService")); NameComponent nc = new NameComponent("Count", ""); NameComponent path[] = {nc}; ncRef.rebind(path, c); FileOutputStream file = new FileOutputStream("Counter.ref"); PrintWriter writer = new PrintWriter(file); String ref = orb.object_to_string(c); writer.println(ref); writer.flush(); file.close(); System.out.println("Server started."+" Stop:Ctrl-c"); rootPOA.the_POAManager().activate(); orb.run(); }catch(IOException ex){ System.out.println("File error:"+ex.getMessage()); System.exit(2); }catch(Exception ex){ System.out.println("Exception: "+ex.getMessage()); System.exit(1); } } }

5 编写并编译客户端程序: Client.java

import CounterApp.*; import java.util.*; import java.io.*; import org.omg.CORBA.*; import org.omg.CosNaming.*; public class Client { public static void main(String[] args){ try{ ORB orb = ORB.init(args, null); org.omg.CORBA.Object obj = orb.resolve_initial_references("NameService"); NamingContext ncRef = NamingContextHelper.narrow(obj); NameComponent nc = new NameComponent("Count",""); NameComponent path[] = {nc}; String ref = null; try{ Scanner reader = new Scanner(new File("Counter.ref")); ref = reader.nextLine(); }catch(IOException ex){ System.out.println("File error: "+ex.getMessage()); System.exit(2); } obj = orb.string_to_object(ref); if(obj == null){ System.out.println("Invalid IOR"); System.exit(4); } Counter c = null; try{ c = CounterHelper.narrow(obj); }catch(BAD_PARAM ex){ System.out.println("Narrowing failed"); System.exit(3); } int inp = -1; do{ System.out.print("Counter value: "+c.value()+"\nAction(+/-/e)?"); System.out.flush(); do{ try{ inp = System.in.read(); }catch(IOException ioe){ } }while(inp != '+' && inp != '-' && inp != 'e'); if(inp == '+') c.inc(); else if(inp == '-') c.dec(); }while(inp != 'e'); }catch(Exception ex){ System.out.println("Exception: "+ex.getMessage()); System.exit(1); } } }

6 运行 （1）启动名字服务器： （2）启动服务端程序：

（3）启动客户端程序：实现自增自减 四．总结 这次上机主要了解了CORBA组件的编程方法，还是很顺利的，刚开始不知道怎么在cmd里改变目录，通过百度了解了，然后因为要输出名字所以在定义并编译对象接口的时候编写的是wstring