走在架構師的大道上 Jack.Wang's home

       1）首先要熟悉idl語言，這個是專門進行接口設計的語言，它與java沒關系，有自己的語法，具體的規則需要大家自己再網上研究，這里不多說了（或者訪問如下網站詳細察看http://www.iona.com/support/docs/manuals/orbix/33/html/orbix33cxx_pguide/IDL.html）。

module HelloApp
{
  
 interface Hello
    {
        string sayHello();
        oneway void shutdown();
     };
};

這 里定義了一個簡單的interface, 將其保存為hello.idl, 然后再dos命令框里面輸入 idlj.exe -fall hello.idl 編譯。之后會出現一個叫做HelloApp的目錄，corba就是通過這個目錄里面的類來進行c-s之間的數據溝通。

      2）下一步，就是我們的server端：

// A server for the Hello object

import HelloApp.*;
import org.omg.CosNaming.*;
import org.omg.CosNaming.NamingContextPackage.*;
import org.omg.CORBA.*;
import org.omg.PortableServer.*;
import org.omg.PortableServer.POA;
import java.util.Properties;

public class HelloServer {

  public static void main(String args[]) {
    try{
      // create and initialize the ORB
      ORB orb = ORB.init(args, null);

      // get reference to rootpoa & activate the POAManager
      POA rootpoa =
        (POA)orb.resolve_initial_references("RootPOA");
      rootpoa.the_POAManager().activate();

      // create servant and register it with the ORB
      HelloImpl helloImpl = new HelloImpl();
      helloImpl.setORB(orb);

      // get object reference from the servant
      org.omg.CORBA.Object ref =
        rootpoa.servant_to_reference(helloImpl);

      // and cast the reference to a CORBA reference
      Hello href = HelloHelper.narrow(ref);
  
      // get the root naming context
      // NameService invokes the transient name service
      org.omg.CORBA.Object objRef =
          orb.resolve_initial_references("NameService");
      // Use NamingContextExt, which is part of the
      // Interoperable Naming Service (INS) specification.
      NamingContextExt ncRef =
        NamingContextExtHelper.narrow(objRef);

      // bind the Object Reference in Naming
      String name = "Hello1";
      NameComponent path[] = ncRef.to_name( name );
      ncRef.rebind(path, href);

      System.out.println
        ("HelloServer ready and waiting ...");

      // wait for invocations from clients
      orb.run();
    }
 
      catch (Exception e) {
        System.err.println("ERROR: " + e);
        e.printStackTrace(System.out);
      }
  
      System.out.println("HelloServer Exiting ...");
 
  } //end main
} // end class

將其保存為HelloServer.java.放在剛才的hello.idl的目錄。編譯這個文件就不多說了。

       3）還記得在hello中定義的interface嗎？我們需要對自己定義的接口中的方法進行實現，因此HelloImp.java

// The servant -- object implementation -- for the Hello
// example.  Note that this is a subclass of HelloPOA, whose
// source file is generated from the compilation of
// Hello.idl using j2idl.

import HelloApp.*;
import org.omg.CosNaming.*;
import org.omg.CosNaming.NamingContextPackage.*;
import org.omg.CORBA.*;
import org.omg.PortableServer.*;
import org.omg.PortableServer.POA;

import java.util.Properties;

class HelloImpl extends HelloPOA //必須繼承這個類，在helloApp目錄中已自動生成

 {
  private ORB orb;

  public void setORB(ORB orb_val) {
    orb = orb_val;
  }
   
  // implement sayHello() method
    public String sayHello()
    {
 return "\nHello world !!\n";
    }
   
  // implement shutdown() method
  public void shutdown() {
    orb.shutdown(false);
  }
} //end class
同樣放在server所在目錄中。

      4）接下來是客戶端（HelloClient.java）：

// A sample Java IDL object client application.
import HelloApp.*;
import org.omg.CosNaming.*;
import org.omg.CosNaming.NamingContextPackage.*;
import org.omg.CORBA.*;

public class HelloClient
{
  static Hello helloImpl;
  String [] x=new String[6];
  public static void main(String args[]){
     try{
        // create and initialize the ORB
      ORB orb = ORB.init(args, null);

        System.out.println("ORB initialised\n");

        // get the root naming context
        org.omg.CORBA.Object objRef =
      orb.resolve_initial_references("NameService");

        // Use NamingContextExt instead of NamingContext,
        // part of the Interoperable naming Service. 
        NamingContextExt ncRef =
          NamingContextExtHelper.narrow(objRef);
 
        // resolve the Object Reference in Naming
        String name = "Hello1";
        helloImpl =
          HelloHelper.narrow(ncRef.resolve_str(name));

        System.out.println
          ("Obtained a handle on server object: "
            + helloImpl);
        System.out.println(helloImpl.sayHello());
        helloImpl.shutdown();

   }
     catch (Exception e) {
        System.out.println("ERROR : " + e) ;
      e.printStackTrace(System.out);
   }
  } //end main

} // end class

這個文件最好放在一個新建的目錄，已表示和server有區別，放在一起也沒有關系。如果分開的話，記著把HelloApp這個目錄復制到client的目錄來。

5）好啦！已經可以開始爽了，我們編譯所有的java文件

6）再dos窗口輸入orbd.exe –ORBInitialPort 1234（端口號可以自定義，但是記得s-c要保持一致）,啟動corba服務。

7）啟動服務器：java HelloServer –ORBInitialPort 1234 –ORBInitialHost localhost

8）啟動客戶端：java HelloClient –ORBInitialPort 1234 –ORBInitialHost localhost

9）嚴格執行上述過程是應該直接成功的。 已經經過測試。