组件化开发方法

题目：1.Java版CORBA程序1——HelloWorld 要求：编写实现显示“Hello，World！+班级+中文姓名”字符串。 2.Java版CORBA程序2——Counter 要求：编写实现连加、连减和加减混合等数学++/- -运算，并进行测试。 一、题目分析 题目1： 1、编写IDL接口HelloWorld.idl 2、编译IDL接口：X:\corba>idlj –fall HelloWorld.idl 3、编写并编译服务端程序:HelloWorldServer.java 4、编写并编译客户端程序: HelloWorldClient.java 5、运行 启动名字服务器：X:\corba >tnameserv -ORBInitialPort 1050 启动服务端程序：X:\corba >java HelloWorldServer -ORBInitialPort 1050 输出：HelloWorld is running 启动客户端程序：X:\corba >java HelloWorldClient -ORBInitialPort 1050 输出：Hello World!软工1702张磊 题目2： 1、编写IDL接口counter.idl： 2、编译IDL接口：X:\corba>idlj –fall counter.idl 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 5、编写并编译客户端程序: Client.java 6、运行 启动名字服务器：X:\corba >tnameserv -ORBInitialPort 1050 启动服务端程序：X:\corba >java Server -ORBInitialPort 1050 输出：Server started. Stop: Ctrl-c 启动客户端程序：X:\corba >java Client -ORBInitialPort 1050 二、CORBA模型分析 当客户端程序要调用远程对象上的方法时，首先要得到这个远程对象的引用，之后就可以像调用本地方法一样调用远程对象的方法。 三、组件实现 题目1：HelloWorld 1、HelloWorld.idl

module sample{ interface HelloWorld{ string 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，例如：中文。

2、X:\corba>idlj –fall counter.idl 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、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!\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、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); } } }

题目2：Counter 1、counter.idl

module CounterApp{ interface Counter{ readonly attribute long value; void inc(); void dec(); }; };

2、X:\corba>idlj –fall counter.idl 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、CounterImpl.java

import CounterApp.*; public class CounterImpl extends CounterPOA { private int count; public CounterImpl(){ count = 0; } public void inc(){ count++; } public void dec(){ count - -; } public int value(){ return count; } }

4、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、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); } } }

四、经验归纳 这次的上机学习了如何进行CORBA组件化开发，对CORBA有了初步的认识，我觉得这种开发方式在实际应用开发中起到很大的作用，通过给定一个接口就能实现在其他地方实现程序功能，这是我以后一定要学习的一个方面。这次根据给定的代码实际运行起来没什么困难，但内部的程序逻辑还不是特别熟习，还需继续努力。