手动实现RPC远程调用

来源：互联网发布：淘宝电风扇编辑：程序博客网时间：2024/04/27 01:55

java中的RPC核心思想就是：socket编程、传输Object、动态代理

package com.lala.rpc;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;import java.net.ServerSocket;import java.net.Socket;public class RpcFramework {/** * 初始化一个服务端socket，一直监听客户端请求，当有请求时，依次读取 方法名称，方法参数类型，方法参数， * 根据这些信息在service上找到相应的method，然后，service方法上执行对应的方法，把方法返回值传输回去 * @param service 暴露的服务接口实现类 * @param port  绑定的端口 * @throws Exception */@SuppressWarnings("resource")public static void publish(final Object service, final int port)throws Exception{final ServerSocket server = new ServerSocket(port);System.out.println("rpc server is start on port : " + port);while(true){final Socket client = server.accept();new Thread(() -> {ObjectInputStream input = null;ObjectOutputStream output = null;try{input = new ObjectInputStream(client.getInputStream());output = new ObjectOutputStream(client.getOutputStream());String methodName = input.readUTF();Class<?>[] pamTypes = (Class<?>[])input.readObject();Object[] args = (Object[])input.readObject();Method method = service.getClass().getMethod(methodName, pamTypes);Object obj = method.invoke(service, args);output.writeObject(obj);}catch(Throwable e){try {output.writeObject(e);} catch (Exception e1){e1.printStackTrace();}}finally{closeStream(output);closeStream(input);closeStream(client);}}).start();}}/** * 根据host, port初始化一个socket，然后传输 方法名称，方法参数类型，方法参数，最后获取服务器返回的结果，就是方法执行的返回值 * @param clazz 调用的接口 * @param host远程服务器 * @param port  端口 * @return * @throws Exception */@SuppressWarnings("unchecked")public static <T> T reference(final Class<T> clazz, final String host, final int port)throws Exception{return (T)Proxy.newProxyInstance(clazz.getClassLoader(), new Class<?>[]{clazz}, new InvocationHandler(){public Object invoke(Object proxy, Method method, Object[] args)throws Throwable {final Socket client = new Socket(host, port);ObjectOutputStream output = new ObjectOutputStream(client.getOutputStream());/** * 往服务端发送方法名称，参数类型，参数 */output.writeUTF(method.getName());output.writeObject(method.getParameterTypes());output.writeObject(args);ObjectInputStream input = new ObjectInputStream(client.getInputStream());try{/** * 获取服务端，方法执行的结果 */Object res = input.readObject();if(res instanceof Throwable){throw (Throwable)res;}return res;}catch(Throwable e){throw e;}finally{closeStream(input);closeStream(output);closeStream(client);}}} );}private static void closeStream(AutoCloseable stream){if(stream != null){try{stream.close();}catch(Exception e){//ignore}}}}

此处写一个测试接口：

package com.lala.rpc;public interface UserService{public String getNameById(String id);}

接口的实现类：

package com.lala.rpc;public class UserServiceImpl implements UserService {public String getNameById(String id) {return "hello " + id;}}

服务端：

package com.lala.rpc;public class Server {public static void main(String[] args) throws Exception{UserService userService = new UserServiceImpl();RpcFramework.publish(userService, 9999);}}

调用客户端：

package com.lala.rpc;public class Client {public static void main(String[] args) throws Exception{UserService userService = RpcFramework.reference(UserService.class, "127.0.0.1", 9999);System.out.println(userService.getNameById("100"));}}

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