Java 实现 RPC(源码)，java 常见面试题

一、RPC 简介

分布式系统的成员之一，解决服务之间的调用问题。远程调用时，RPC 实现了调用远程服务能够像本地调用一样方便，让调用者感知不到远程调用的逻辑。

二、RPC 组成成员

• 动态代理

• 序列化

• 网络传输

• 调用服务 API 接口

本次 RPC 搭建使用的接口代理模式、Java 默认 Serializable 序列化以及 BIO 网络传输方式

三、源码实现

• 动态代理模块封装

package com.ruider.Invoker;

/**

• 动态代理工厂，对相应的 class 生产其对应代理类

*/

import com.ruider.common.ServiceInformation;

import com.ruider.networkCommunication.BIOService;

import com.ruider.networkCommunication.NetIO;

import java.lang.reflect.InvocationHandler;

import java.lang.reflect.Method;

import java.lang.reflect.Proxy;

public class InvokerUtils implements InvocationHandler {

/**

• 调用服务类

*/

private Class clazz;

/**

• 调用服务管理

*/

private ServiceInformation serviceInformation;

/**

• 获取代理对象

• @param T

• @param url

• @param port

• @return

*/

public Object getBean (Class T, String url, int port) {

this.clazz = T;

ServiceInformation serviceInformation = new ServiceInformation();

serviceInformation.setServiceURL(url);

serviceInformation.setPort(port);

serviceInformation.setClassName(T.getName());

this.serviceInformation = serviceInformation;

return Proxy.newProxyInstance(T.getClassLoader(), new Class[]{T}, this);

}

@Override

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

NetIO BIO = new BIOService();

this.serviceInformation.setMethod(method);

this.serviceInformation.setArgs(args);

return BIO.send(serviceInformation);

}

}

• 网络传输模块封装

package com.ruider.networkCommunication;

import com.ruider.common.ServiceInformation;

/**

• BIO 服务

*/

public interface NetIO {

/**

• 客户端发送请求到其他服务端

• @param serviceInformation

• @return

*/

Object send (ServiceInformation serviceInformation);

/**

• 本机作为服务端接受请求并且处理请求

• @param port

*/

void recv (int port);

}

package com.ruider.networkCommunication;

import com.ruider.common.ServiceInformation;

import com.ruider.common.UserApi;

import com.ruider.server.UserService;

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;

/**

• 使用 BIO 通信

*/

public class BIOService implements NetIO {

/**

• 主机 IP

*/

private String url;

/**

• 端口

*/

private int port;

/**

• 客户端 socket

*/

private Socket clientSocket;

/**

• 服务端 socket

*/

private ServerSocket serverSocket;

public BIOService() {}

public BIOService(String url, int port) {

this.url = url;

this.port = port;

}

/**

• 客户端采用 BIO 通信方式发送请求信息

• @param serviceInformation

• @return

*/

@Override

public Object send(ServiceInformation serviceInformation) {

ObjectOutputStream objectOutputStream = null;

ObjectInputStream objectInputStream = null;

try {

this.clientSocket = new Socket(serviceInformation.getServiceURL(), serviceInformation.getPort());

String className = serviceInformation.getClassName();

String methodName = serviceInformation.getMethod().getName();

Class<?>[] parameterTypes = serviceInformation.getMethod().getParameterTypes();

Object[] args = serviceInformation.getArgs();

objectOutputStream = new ObjectOutputStream(this.clientSocket.getOutputStream());

objectOutputStream.writeUTF(className);

objectOutputStream

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.writeUTF(methodName);

objectOutputStream.writeObject(parameterTypes);

objectOutputStream.writeObject(args);

objectInputStream = new ObjectInputStream(this.clientSocket.getInputStream());

Object o = objectInputStream.readObject();

System.out.println("Object = " + o);

return o;

}

catch (Exception e) {

if (this.clientSocket != null) {

try {

this.clientSocket.close();

}catch (IOException e1) {

e1.printStackTrace();

}

}

if (objectOutputStream != null) {

try {

objectOutputStream.close();

}catch (IOException e1) {

e1.printStackTrace();

}

}

if (objectInputStream != null) {

try {

objectInputStream.close();

}catch (IOException e1) {

e1.printStackTrace();

}

}

return null;

}

finally {

if (this.clientSocket != null) {

try {

this.clientSocket.close();

}catch (IOException e1) {

e1.printStackTrace();

}

}

if (objectOutputStream != null) {

try {

objectOutputStream.close();

}catch (IOException e1) {

e1.printStackTrace();

}

}

if (objectInputStream != null) {

try {

objectInputStream.close();

}catch (IOException e1) {

e1.printStackTrace();

}

}

}

}

/**

• 服务端采用 BIO 通信获取数据

• @return

*/

@Override

public void recv (int port) {

ObjectInputStream objectInputStream = null;

ObjectOutputStream objectOutputStream = null;

try {

this.serverSocket = new ServerSocket(port);

System.out.println("启动远程服务监听...");

//监听客户端发来消息

while (true){

Socket socket = serverSocket.accept();

objectInputStream = new ObjectInputStream(socket.getInputStream());

//客户端传输类名

String className = objectInputStream.readUTF();

String methodName = objectInputStream.readUTF();

Class<?>[] parameterTypes = (Class<?>[])objectInputStream.readObject();

Object[] arguments = (Object[]) objectInputStream.readObject();

Class clazz = null;

//服务匹配

if(className.equals(UserApi.class.getName())){

clazz = UserService.class;

}

//clazz = UserService.class;

Method method = clazz.getMethod(methodName,parameterTypes);

Object result = method.invoke(clazz.newInstance(),arguments);

objectOutputStream = new ObjectOutputStream(socket.getOutputStream());

objectOutputStream.writeObject(result);

objectOutputStream.flush();

socket.close();

}

} catch (Exception e) {

try {

if (objectOutputStream != null) {

objectOutputStream.close();

}

if (objectInputStream != null) {

objectInputStream.close();

}

if (this.serverSocket != null) {

this.serverSocket.close();

}

}

catch (IOException e1) {

e1.printStackTrace();

}