java - 通过互联网的 RMI iiop

Question

我正在尝试获取 Oracle RMI-IIOP example工作，但我在 Netbeans 中执行此操作时遇到问题。

我的代码如下:

界面

import java.rmi.Remote;
import java.rmi.RemoteException;

public interface HelloInterface extends Remote {
    public void sayHello(String from) throws RemoteException;
}

接口(interface)实现

import java.rmi.RemoteException;
import javax.rmi.PortableRemoteObject;

public class HelloImpl extends PortableRemoteObject implements HelloInterface{
    public HelloImpl() throws RemoteException
    {
        super();
    }

    public void sayHello(String from) throws RemoteException
    {
        System.out.println("Hello from " + from + "!!!");
        System.out.flush();
    }
}

服务器主

import javax.naming.Context;
import javax.naming.InitialContext;

public class HelloServer {

    public static void main(String[] args) {
        try {

            System.setProperty("java.naming.factory.initial", "com.sun.jndi.cosnaming.CNCtxFactory");
            System.setProperty("java.naming.provider.url", "iiop://localhost:1050");
            // Step 1: Instantiate the Hello servant
            HelloImpl helloRef = new HelloImpl();
            // Step 2: Publish the reference in the Naming Service
            // using JNDI API
            Context initialNamingContext = new InitialContext();
            initialNamingContext.rebind("HelloService", helloRef);
            System.out.println("Hello Server: Ready...");
        } catch (Exception e) {
            System.out.println("Trouble: " + e);
            e.printStackTrace();
        }
    }
}

和客户端代码

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.rmi.PortableRemoteObject;

public class HelloRMIIIOPClient {

    public static void main(String[] args) {
        Context ic;
        Object objref;
        HelloInterface hi;
        try {
            ic = new InitialContext();
            System.setProperty("classpath", ".");
            System.setProperty("java.naming.factory.initial", "com.sun.jndi.cosnaming.CNCtxFactory");
            System.setProperty("java.naming.provider.url", "iiop://localhost:1050");
        // STEP 1: Get the Object reference from the Name Service
        // using JNDI call.
            objref = ic.lookup("HelloService");
            System.out.println("Client: Obtained a ref. to Hello server.");
        // STEP 2: Narrow the object reference to the concrete type and
        // invoke the method.
            hi = (HelloInterface) PortableRemoteObject.narrow(
                objref, HelloInterface.class);
            hi.sayHello( " MARS " );

        } catch( Exception e ) {
            System.err.println( "Exception " + e + "Caught" );
            e.printStackTrace( );
            return;
        }
    }
}

我使用 rmic 生成 stub 和骨架，代码的服务器部分工作正常，但是当我运行客户端代码时，我得到:

Exception javax.naming.NoInitialContextException: Need to specify class name in environment or system property, or as an applet parameter, or in an application resource file:  java.naming.factory.initialCaught
javax.naming.NoInitialContextException: Need to specify class name in environment or system property, or as an applet parameter, or in an application resource file:  java.naming.factory.initial
        at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:645)
        at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:288)
        at javax.naming.InitialContext.getURLOrDefaultInitCtx(InitialContext.java:325)
        at javax.naming.InitialContext.lookup(InitialContext.java:392)
        at hellormiiiopnew.HelloRMIIIOPClient.main(HelloRMIIIOPClient.java:33)
BUILD SUCCESSFUL (total time: 0 seconds)

虽然这只是为了让我了解其工作原理，但最终代码将用作模板，因此我可以通过互联网在分布式系统上传输简单的对象。我一直在尝试让 RMI 在互联网上工作，但没有成功，所以这是我的最新尝试。任何帮助，尤其是示例，将不胜感激。

Answer 1

您需要在创建InitialContext 之前设置系统属性。