JAVA反射示例四——结合代理模式的远程方法调用事例

luweifeng1983

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;  }}
接口类与实现类
package proxy1;import java.util.Date;public interface HelloService{  public String echo(String msg)throws RemoteException;  public Date getTime()throws RemoteException;} package proxy1;import java.util.Date;public class HelloServiceImpl implements HelloService{  public String echo(String msg){    return "echo:"+msg;  }  public Date getTime(){    return new Date();  }}
Connector类进行连接读写对象
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);      }    }  }}
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);  }}
自定义异常
package proxy1;public class RemoteException extends Exception{  public RemoteException(Throwable e){    super(e);  }}
客户端类
package proxy1;import java.io.*;import java.net.*;import java.util.*;public class SimpleClient {  public static void main(String args[])throws Exception {     //创建静态代理类实例    HelloService helloService1=new HelloServiceProxy("localhost",8000);    System.out.println(helloService1.echo("hello"));    System.out.println(helloService1.getTime());    //创建动态代理类实例    HelloService helloService2=         (HelloService)ProxyFactory.getProxy(HelloService.class,"localhost",8000);    System.out.println(helloService2.echo("hello"));    System.out.println(helloService2.getTime());  }}
服务器端类
package proxy1;import java.io.*;import java.net.*;import java.util.*;import java.lang.reflect.*;public class SimpleServer {  private Map remoteObjects=new HashMap();    public void register(String className,Object remoteObject){    remoteObjects.put( className,remoteObject);  }   public void service()throws Exception{    ServerSocket serverSocket = new ServerSocket(8000);    System.out.println("服务器启动.");    while(true){      Socket socket=serverSocket.accept();      InputStream in=socket.getInputStream();      ObjectInputStream ois=new ObjectInputStream(in);      OutputStream out=socket.getOutputStream();      ObjectOutputStream oos=new ObjectOutputStream(out);      Call call=(Call)ois.readObject();      System.out.println(call);      call=invoke(call);      oos.writeObject(call);            ois.close();      oos.close();      socket.close();    }  }  public Call invoke(Call call){    Object result=null;    try{      String className=call.getClassName();      String methodName=call.getMethodName();      Object[] params=call.getParams();      Class classType=Class.forName(className);       Class[] paramTypes=call.getParamTypes();      Method method=classType.getMethod(methodName,paramTypes);        Object remoteObject=remoteObjects.get(className);      if(remoteObject==null){        throw new Exception(className+"的远程对象不存在");      }else{        result=method.invoke(remoteObject,params);      }    }catch(Exception e){result=e;}    call.setResult(result);    return call;  }  public static void main(String args[])throws Exception {    SimpleServer server=new SimpleServer();    server.register("proxy1.HelloService",new HelloServiceImpl());    server.service();  }}