JAVA反射示例四——结合代理模式的远程方法调用事例
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();}}
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