RMI 示例

RMI（Remote Method Invocation）
    RMI是分布式对象软件包，它简化了在多台计算机上的JAVA应用之间的通信。

public interface Fibonacci extends Remote {
 public BigInteger getFibonacci(int n) throws RemoteException;
 public BigInteger getFibonacce(BigInteger n) throws RemoteException;
}

 

public class FibonacciImpl extends UnicastRemoteObject implements Fibonacci {

public FibonacciImpl() throws RemoteException{
  super();
 }
 
 public BigInteger getFibonacci(int n) throws RemoteException{
  return this.getFibonacce(new BigInteger(Long.toString(n)));
 }
 
 public BigInteger getFibonacce(BigInteger n) throws RemoteException {
  System.out.println("Calculating the" + n +"th Fibonacci number");
  BigInteger zero = new BigInteger("0");
  BigInteger one = new BigInteger("1");
  
  if(n.equals(zero)) return one;
  if(n.equals(one)) return one;
  
  BigInteger i = one;
  BigInteger low = one;
  BigInteger high = one;
  
  while(i.compareTo(n) == -1){
   BigInteger temp = high;
   high = high.add(low);
   low = temp;
   i = i.add(one);
  }
  return high;
 }
}

 

public class FibonacciServer {

 //服务器启动

public static void main(String[] args) {
  
  try {
   //加载安全管理器
   //System.setSecurityManager(new RMISecurityManager() );
   System.out.println("begin 1");
   FibonacciImpl f = new FibonacciImpl();
   Naming.rebind("fibonacci", f);
   System.out.println("Fibonacci Server ready.");
   
  } catch (RemoteException e) {
   e.printStackTrace();
  } catch (MalformedURLException e1) {
   e1.printStackTrace();
  }
 }
}

 

public class FibonacciClient {

 /**
  * @param args客户端
  */
 public static void main(String[] args) {
  String rmiUrl = "rmi://localhost/fibonacci";
  BigInteger index = new BigInteger("30");
  
  try {
   Object o  = Naming.lookup(rmiUrl);
   Fibonacci calculator = (Fibonacci)o;
   BigInteger f = calculator.getFibonacce(index);
   System.out.println("The " + index + "th Fibonacci number is "+ f);
  } catch (Exception e) {
   e.printStackTrace();
  }
 }

}

复制以上代码到Eclipse,按如下步骤操作：

1、编译桩: 在windows中，在DOS提示符下运行 rmic 包.FibonacciImpl

2、确保所有桩和服务器类位于服务器的类路径中。

3、在windows中，要在DOS提示符下启动注册表，如下：C：\start rmiregistry

4、运行FibonacciServer 和 FibonacciClient 即可