深沉的船

现在虽然我们很少用到RMI进行编程，但是做为Java一个最早的分布式解决方案，我们还是有了解的必要，从例子开始吧（虽然是几年前的了）！

远程接口RmiHelloRemoteIntfc .java

import java.rmi.*;

public interface RmiHelloRemoteIntfc extends Remote
{
   String helloRemoteObj(String client) throws RemoteException;
}

import java.rmi.*;<br/><br/>public interface RmiHelloRemoteIntfc extends Remote<br/>{<br/> String helloRemoteObj(String client) throws RemoteException;<br/>}

远程接口的实现类RmiHelloRemoteObj.java

import java.rmi.server.*;
import java.rmi.*;

public class RmiHelloRemoteObj extends UnicastRemoteObject implements RmiHelloRemoteIntfc
{

  public RmiHelloRemoteObj() throws RemoteException
  {
    super();
  }

  public String helloRemoteObj(String client) throws RemoteException
  {
     return "Hello World"+client;
  }

}

import java.rmi.server.*;<br/>import java.rmi.*;<br/><br/>public class RmiHelloRemoteObj extends UnicastRemoteObject implements RmiHelloRemoteIntfc<br/>{<br/><br/> public RmiHelloRemoteObj() throws RemoteException<br/> {<br/> super();<br/> }<br/><br/> public String helloRemoteObj(String client) throws RemoteException<br/> {<br/> return "Hello World"+client;<br/> }<br/><br/>}

服务器类RmiHelloServer.java

import java.io.*;
import java.rmi.*;
import java.rmi.server.*;
import sun.applet.*;
import java.rmi.registry.LocateRegistry;

public class RmiHelloServer
{

  public RmiHelloServer()
  {
  }
  public static void main(String[] args)
  {
    //创建并安装安全管理器
    if(System.getSecurityManager()==null)
    {
       System.setSecurityManager(new RMISecurityManager());
    }

    try{
         //创建远程对象
         RmiHelloRemoteObj ttt=new RmiHelloRemoteObj();
         //启动注册表
         LocateRegistry.createRegistry(2222);
         //奖名称绑定到对象
         Naming.rebind("//Fangm:2222/helloObj",ttt);

         System.out.println("RMI服务器正在运行。。。。。。");
      }
      catch(Exception e)
      {
         e.printStackTrace();
      }


  }
}

import java.io.*;<br/>import java.rmi.*;<br/>import java.rmi.server.*;<br/>import sun.applet.*;<br/>import java.rmi.registry.LocateRegistry;<br/><br/>public class RmiHelloServer<br/>{<br/><br/> public RmiHelloServer()<br/> {<br/> }<br/> public static void main(String[] args)<br/> {<br/> //创建并安装安全管理器<br/> if(System.getSecurityManager()==null)<br/> {<br/> System.setSecurityManager(new RMISecurityManager());<br/> }<br/><br/> try{<br/> //创建远程对象<br/> RmiHelloRemoteObj ttt=new RmiHelloRemoteObj();<br/> //启动注册表<br/> LocateRegistry.createRegistry(2222);<br/> //奖名称绑定到对象<br/> Naming.rebind("//Fangm:2222/helloObj",ttt);<br/><br/> System.out.println("RMI服务器正在运行。。。。。。");<br/> }<br/> catch(Exception e)<br/> {<br/> e.printStackTrace();<br/> }<br/><br/><br/> }<br/>}

服务器端的权限文件RmiHelloServer.policy

grant codeBase "file:/e:/download/rmitest/" {  permission java.net.SocketPermission       "*:1000-9999","accept,connect,listen,resolve"; };



现在就看看Client端是如何连接服务器和进行远程方法的调用的吧

import java.rmi.*;
import java.rmi.server.*;

public class RmiHelloClient
{

  public RmiHelloClient()
  {
  }
  public static void main(String[] args)
  {
    //创建并安装安全管理器
    if(System.getSecurityManager()==null)
    {
       System.setSecurityManager(new RMISecurityManager());
    }

    try{
          RmiHelloRemoteIntfc c1=(RmiHelloRemoteIntfc)Naming.lookup("rmi://Fangm:2222/helloObj");
          System.out.println(c1.helloRemoteObj("Everyone"));
    }
    catch(Exception e)
    {
       e.printStackTrace();
    }
    System.exit(0);

 

  }
}

import java.rmi.*;<br/>import java.rmi.server.*;<br/><br/>public class RmiHelloClient<br/>{<br/><br/> public RmiHelloClient()<br/> {<br/> }<br/> public static void main(String[] args)<br/> {<br/> //创建并安装安全管理器<br/> if(System.getSecurityManager()==null)<br/> {<br/> System.setSecurityManager(new RMISecurityManager());<br/> }<br/><br/> try{<br/> RmiHelloRemoteIntfc c1=(RmiHelloRemoteIntfc)Naming.lookup("rmi://Fangm:2222/helloObj");<br/> System.out.println(c1.helloRemoteObj("Everyone"));<br/> }<br/> catch(Exception e)<br/> {<br/> e.printStackTrace();<br/> }<br/> System.exit(0);<br/><br/> <br/><br/> }<br/>}

Client端的权限文件RmiHelloClient.policy

grant codeBase "file:/e:/download/rmitest/" {   permission java.net.SocketPermission       "*:1000-9999","accept,connect,listen,resolve"; };

好了，一个最简单的RMI例子就安无了，对了还少了最重要的一步，那就是编译和运行呢？我们就来了个Bat或Cmd的批处理来进行吧，

看看RmiHello.bat吧

javac RmiHelloRemoteIntfc.java javac RmiHelloRemoteObj.java rmic RmiHelloRemoteObj javac RmiHelloServer.java javac RmiHelloClient.java echo 在另一个窗口启动服务器，请稍后。。。 start java  -Djava.security.policy=RmiHelloServer.policy RmiHelloServer echo 运行客户程序。。。 java -Djava.security.policy=RmiHelloClient.policy RmiHelloClient

这个文件很简单吧！包你一试就通，虽然简单，不过对于初学者来说，还是很不错的哦！