在远程方法调用中运用 《代理类》

//Connector.java

package proxy1;

import java.io.*;

import java.net.*;

import java.util.*;

public class Connector {

  private String host;

  private int port;

  private Socket skt;

  private InputStream is;

  private ObjectInputStream ois;

  private OutputStream os;

  private ObjectOutputStream oos;

  public Connector(String host,int port)throws Exception{

     this.host=host;

     this.port=port;

     connect(host,port);

  }

  public void send(Object obj)throws Exception{

    oos.writeObject(obj);

  }

  public Object receive() throws Exception{

    return ois.readObject();

  }

  public void connect()throws Exception{

    connect(host,port);

  }

  public void connect(String host,int port)throws Exception{

    skt=new Socket(host,port);

    os=skt.getOutputStream();

    oos=new ObjectOutputStream(os);

    is=skt.getInputStream();

    ois=new ObjectInputStream(is);

  }

  public void close(){

    try{

    }finally{

      try{

        ois.close();

        oos.close();

        skt.close();

      }catch(Exception e){

        System.out.println("Connector.close: "+e);

      }

    }

  }

}

//Call.java

package proxy1;

import java.io.*;

public class Call implements Serializable{

  private String className;  //表示类名

  private String methodName; //表示方法名

  private Class[] paramTypes; //表示方法参数类型

  private Object[] params; //表示方法参数值

  private Object result;  //表示方法的返回值或者方法抛出的异常

  

  public Call(){}

  public Call(String className,String methodName,Class[] paramTypes,

                            Object[] params){

    this.className=className;

    this.methodName=methodName;

    this.paramTypes=paramTypes;

    this.params=params;

  }

  

  public String getClassName(){return className;}

  public void setClassName(String className){this.className=className;}

  public String getMethodName(){return methodName;}

  public void setMethodName(String methodName){this.methodName=methodName;}

  public Class[] getParamTypes(){return paramTypes;}

  public void setParamTypes(Class[] paramTypes){this.paramTypes=paramTypes;}

  public Object[] getParams(){return params;}

  public void setParams(Object[] params){this.params=params;}

  public Object getResult(){return result;}

  public void setResult(Object result){this.result=result;}

  public String toString(){

    return "className="+className+" methodName="+methodName;

  }

} 

 //RemoteException.java

 

package proxy1;

 

public class RemoteException extends Exception{

  public RemoteException(Throwable e){

    super(e);

  }

}

 

 

 //静态代理类

package proxy1;

import java.util.Date;

public class HelloServiceProxy implements HelloService{

  private String host;

  private int port;

  

  public HelloServiceProxy(String host,int port){

     this.host=host;

     this.port=port;

  }

  public String echo(String msg)throws RemoteException{

    Connector connector=null;

    try{

      connector=new Connector(host,port);

      Call call=new Call("proxy1.HelloService","echo",new Class[]{String.class},new Object[]{msg}); 

      connector.send(call);

      call=(Call)connector.receive();

      Object result=call.getResult();

      if(result instanceof Throwable)

        throw new RemoteException((Throwable)result);

      else

        return (String)result;

    }catch(Exception e){

       throw new RemoteException(e);

    }finally{if(connector!=null)connector.close();}

  }

  public Date getTime()throws RemoteException{

    Connector connector=null;

    try{

      connector=new Connector(host,port);

      Call call=new Call("proxy1.HelloService","getTime",new Class[]{},new Object[]{}); 

      connector.send(call);

      call=(Call)connector.receive();

      Object result=call.getResult();

      if(result instanceof Throwable)

        throw new RemoteException((Throwable)result);

      else

        return (Date)result;

     }catch(Exception e){

       throw new RemoteException(e);

     }finally{if(connector!=null)connector.close();}

  }

} 

 //动态代理类

package proxy1;

import java.lang.reflect.*;

public class ProxyFactory {

  public static Object getProxy(final Class classType,final String host,final int port){

    InvocationHandler handler=new InvocationHandler(){

      public Object invoke(Object proxy,Method method,Object args[])

                                                       throws Exception{

        Connector connector=null;

        try{

          connector=new Connector(host,port);

          Call call=new Call(classType.getName(),

              method.getName(),method.getParameterTypes(),args); 

          connector.send(call);

          call=(Call)connector.receive();

          Object result=call.getResult();

          if(result instanceof Throwable)

            throw new RemoteException((Throwable)result);

          else

            return result;

        }finally{if(connector!=null)connector.close();}

      }

    };

    return Proxy.newProxyInstance(classType.getClassLoader(),

                                          new Class[]{classType},

                                          handler);

  }

}