Java远程方法调用中动态代理类的使用

客户端 和 服务端公用文件
share
    |__call
    |       |__Call.java
    |__service
             |__HelloService.java
客户端代码
locale
    |__client
             |__SimpleClient.java
             |__ProxyFactory.java
             |__TcpConnector.java
服务端代码
remote
     |__server
     |        |__SimpleServer.java
     |__service
              |__HelloServiceImpl.java
程序实现目标
    客户端通过动态代理类调用服务端HelloServiceImpl.java 中的方法

 

// share.call.Call.java
package share.call;

import java.io.Serializable;

/**
 *@date 2010-3-13 下午04:32:04
 *@author dycc
 *@file share.call.Call.java
 */
public class Call implements Serializable{
    /**
     *
     */
    private static final long serialVersionUID = 1L;
    private String className;
    private String methodName;
    @SuppressWarnings(value="unchecked")
    private Class[] paramTypes;
    private Object[] params;
    private Object result;

    public Call(){
    }
    @SuppressWarnings(value="unchecked")
    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;
    }
    @SuppressWarnings(value="unchecked")
    public Class[] getParamTypes() {
        return paramTypes;
    }
    @SuppressWarnings(value="unchecked")
    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(){
        StringBuffer sb = new StringBuffer();
        sb.append("{className=" + className);
        sb.append(",methodName=" + methodName);
        sb.append(",result=" + result);
        sb.append("}");
        return sb.toString();
    }
}

// share.service.HelloService.java
package share.service;

import java.util.Date;

/**
 *@date 2010-3-13 下午04:29:29
 *@author dycc
 *@file share.service.HelloService.java
 */
public interface HelloService {
    public String echo(String msg);
    public Date getTime();
}

// locale.client.SimpleClient.java
package locale.client;

import share.service.HelloService;

/**
 *@date 2010-3-13 下午04:58:48
 *@author dycc
 *@file locale.client.SimpleClient.java
 */
public class SimpleClient {
    /**
     * 通过代理类调用远程方法
     */
    public void invoke(){
        HelloService hello = (HelloService)ProxyFactory.getProxy(
                HelloService.class,"remote.service.HelloServiceImpl",
                "localhost", 8002);
        String result = hello.echo("music");
        System.out.println("result=" + result);
    }

    public static void main(String[] args){
        SimpleClient client = new SimpleClient();
        client.invoke();
    }
}

// locale.client.ProxyFactory.java
package locale.client;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.rmi.RemoteException;

import share.call.Call;

/**
 *@date 2010-3-13 下午08:21:01
 *@author dycc
 *@file locale.client.ProxyFactory.java
 */
public class ProxyFactory {
    /**
     * 获取动态代理类
     * @param classType 接口
     * @param className 实现类名称
     * @param ip        ip 地址
     * @param port      端口
     * @return
     */
    @SuppressWarnings(value="unchecked")
    public static Object getProxy(Class classType,
            final String className,
            final String ip,final int port){
        // start
        InvocationHandler handler = new InvocationHandler(){
            public Object invoke(Object proxy, Method method, Object[] args)
                    throws Throwable {
                System.out.println("--- before " + method.getName() + "---");
                TcpConnector connector = new TcpConnector(ip, port);
                Call call = new Call(className,method.getName(),
                        method.getParameterTypes(),args);
                call = (Call)connector.invoke(call);
                Object result = call.getResult();
                if(result instanceof Throwable){
                    return new RemoteException(method.getName() + "invoke failed",
                            (Throwable)result);
                }
                System.out.println("--- after " + method.getName() + "---");
                connector.close();
                return result;
            }
        };
        return Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),
                new Class[]{classType}, handler);
    }
}

// locale.client.TcpConnector.java
package locale.client;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.Socket;

/**
 *@date 2010-3-13 下午08:25:04
 *@author dycc
 *@file locale.client.TcpConnector.java
 */
public class TcpConnector {
    private Socket socket;
    private ObjectInputStream in;
    private ObjectOutputStream out;
    /**
     * 构造器
     * @param ip
     * @param port
     * @throws IOException
     */
    public TcpConnector(String ip,int port)throws IOException{
        socket = new Socket(ip,port);
    }
    /**
     * 调用远程方法
     * @param obj
     * @throws IOException
     */
    public Object invoke(Object obj)throws IOException,ClassNotFoundException{
        if(out == null){
            out = new ObjectOutputStream(socket.getOutputStream());
        }
        out.writeObject(obj);
        out.flush();
        if(in == null){
            in = new ObjectInputStream(socket.getInputStream());
        }
        return in.readObject();
    }
    /**
     * 关闭连接
     */
    public void close(){
        try{
            if(in != null){
                in.close();
            }
            if(out != null){
                out.close();
            }
            if(socket != null){
                socket.close();
            }
        } catch(Exception e){
        }
    }
}

// remote.server.SimpleServer.java
package remote.server;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Method;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.Map;

import share.call.Call;


/**
 *@date 2010-3-13 下午04:38:44
 *@author dycc
 *@file remote.server.SimpleServer.java
 */
public class SimpleServer {
    private Map<String,Object> map_objs = new HashMap<String,Object>();
    private ObjectInputStream in;
    private ObjectOutputStream out;
    /**
     * 服务端在 8002 端口监听客户端请求
     * @throws IOException
     */
    public void service()throws IOException{
        ServerSocket server_socket = new ServerSocket(8002);
        System.out.println("----- server started. -----");
        while(true){
            try{
                Socket socket = server_socket.accept();
                // ObjectInputStream 会发生阻塞!!
                in = new ObjectInputStream(socket.getInputStream());
                Call call = (Call)in.readObject();
                System.out.println("-- get call [" + call.getClassName()
                                   + ":" + call.getMethodName() + "]");
                call = invoke(call);
                out = new ObjectOutputStream(socket.getOutputStream());
                out.writeObject(call);
                out.flush();
            } catch(Exception e){
                e.printStackTrace();
            } finally{
                try{
                    if(in != null){
                        in.close();
                    }
                    if(out != null){
                        out.close();
                    }
                } catch(Exception e){
                }
            }
        }
    }
    /**
     * 调用 call 所指定的的方法
     * @param call
     * @return
     */
    public Call invoke(Call call){
        Object obj = map_objs.get(call.getClassName());
        if(obj == null){
            try {
                obj = Class.forName(call.getClassName()).newInstance();
                map_objs.put(call.getClassName(), obj);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        try {
            Method method = obj.getClass().getMethod(
                            call.getMethodName(),
                            call.getParamTypes());
            Object result = method.invoke(obj, call.getParams());
            call.setResult(result);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return call;
    }

    public static void main(String[] args)throws Exception{
        SimpleServer server = new SimpleServer();
        server.service();
    }
}

// remote.service.HelloServiceImpl.java
package remote.service;

import java.util.Date;

import share.service.HelloService;

/**
 *@date 2010-3-13 下午04:30:44
 *@author dycc
 *@file remote.service.HelloServiceImpl.java
 */
public class HelloServiceImpl implements HelloService{
    public String echo(String msg) {
        return "echo:" + msg;
    }
    public Date getTime() {
        return new Date();
    }
}