手写一个简单的RPC框架

Posted 2023-03-23 一杯java不加糖

学习RPC框架，由繁化简，了解其本质原理

文章目录

• 项目简介
• • 什么是RPC？
  • 项目模块
• 项目代码
• • common模块
  • client模块
  • server模块
  • framework模块
  • 测试

项目简介

什么是RPC？

RPC（Remote Procedure Call）即远程过程调用，不同于本地调用，RPC是指调用远端机器的函数或方法，且不需要关心底层的调用细节，如网络协议和传输协议等，对于调用者来说，和调用本地方法没有什么区别。

项目模块

1. common模块：定义了用户接口和实体类User
2. client模块：调用RPC框架的代理类，获取结果
3. server模块：

• 实现common的接口，把实现类注册到注册中心中
• 调用RpcServer开启socket
• 根据RpcRequest类的信息，获取到注册中心的实现类
• 执行方法，返回结果，通过socket返回

4. Rpc framework

• 注册中心
• RpcRequest，装载类的信息
• RpcServer：创建socket，接受客户端的请求

项目代码

common模块

实体类和定义的接口

package com.rpc.common;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.io.Serializable;

/**
 * @Author: Yangmiao
 * @Date: 2023/2/8 10:37
 * @Desc: 网络中传输的信息
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class User implements Serializable 

    private Integer id;

    private String name;

    private Integer age;

    private int sex;

package com.rpc.common;

/**
 * @Author: Yangmiao
 * @Date: 2023/2/8 10:38
 * @Desc:
 */
public interface IUserService 
    User getById(Integer id);

    User getUsername(String userName);

client模块

package com.rpc.client;

import com.rpc.common.IUserService;
import com.rpc.framework.proxy.RpcProxy;

/**
 * @Author: Yangmiao
 * @Date: 2023/2/8 11:39
 * @Desc:
 */
public class Client 
    public static void main(String[] args) 
        RpcProxy rpcProxy = new RpcProxy();
        IUserService productService = (IUserService) rpcProxy.remoteCall("localhost", 10000, IUserService.class);
        System.out.println("productService = " + productService.getById(10));
    

server模块

package com.rpc.server;

import com.rpc.common.IUserService;
import com.rpc.framework.Registry;
import com.rpc.framework.RpcServer;

/**
 * @Author: Yangmiao
 * @Date: 2023/2/8 11:37
 * @Desc:
 * https://www.cnblogs.com/fantongxue/p/16004920.html
 */
public class Server 
    /**
     * 把接口和实现类注册到RPC的注册中心，然后通过RPC的RPCServer开启一个serversocket，监听某一个端口。
     * @param args
     */
    public static void main(String[] args) 
        Registry.put(IUserService.class.getName(), UserServiceImpl.class);
        new RpcServer().provide(10000);
    

package com.rpc.server;

import com.rpc.common.User;
import com.rpc.common.IUserService;

/**
 * @Author: Yangmiao
 * @Date: 2023/2/8 11:35
 * @Desc:
 */
public class UserServiceImpl implements IUserService 
    @Override
    public User getById(Integer id) 
        return User.builder()
                .id(id)
                .name("yangmiao")
                .age(100)
                .sex(1)
                .build();
    

    @Override
    public User getUsername(String userName) 
        return User.builder()
                .name(userName)
                .build();
    

framework模块

package com.rpc.framework;

import java.util.HashMap;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
 * @Author: Yangmiao
 * @Date: 2023/2/8 10:39
 * @Desc: 注册中心
 */
public class Registry 
    private final static HashMap<String, Class> map = new HashMap<>();
    private final static ReadWriteLock readWriteLock = new ReentrantReadWriteLock();

    /**
     * 读缓存
     * @param key
     * @return
     */
    public static Class get(String key)
        // 读锁
        Lock writeLock = readWriteLock.writeLock();
        // 写锁
        Lock readLock = readWriteLock.readLock();

        Class v = null;
        readLock.lock();
        try 
            v = map.get(key);
        finally 
            readLock.unlock();
        
        if (v != null)
            return v;
        
        // 缓存中不存在
        writeLock.lock();
        try 
            v = map.get(key);
            if (v==null)
                // 1.查询数据库
                // 2.写入缓存
                map.put(key,v);
            
        finally 
            writeLock.unlock();
        
        return v;
    

    /**
     * 写缓存
     * @param key
     * @param value
     * @return
     */
    public static Class put(String key, Class value)
        Lock writeLock = readWriteLock.writeLock();
        writeLock.lock();
        try 
            return map.put(key,value);
        finally 
            writeLock.unlock();
        
    

    public static boolean containsKey(String key)
        return map.containsKey(key);
    

package com.rpc.framework;

import lombok.Data;

import java.io.Serializable;

/**
 * @Author: Yangmiao
 * @Date: 2023/2/8 10:41
 * @Desc:
 */
@Data
public class RpcRequest implements Serializable 

    private String className;

    private String methodName;

    private Class[] types;

    private Object[] params;

package com.rpc.framework;


import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * @Author: Yangmiao
 * @Date: 2023/2/8 10:42
 * @Desc:
 */
public class RpcServer 
    /**
     * 创建线程池
     */
    private ExecutorService executors = Executors.newFixedThreadPool(5);

    public void provide(int port)
        try 
            ServerSocket serverSocket = new ServerSocket(port);
            while (true)
                Socket socket = serverSocket.accept();
                executors.execute(new ProcessHandler(socket));
            
         catch (IOException e) 
            e.printStackTrace();
        
    

package com.rpc.framework;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.Socket;

/**
 * @Author: Yangmiao
 * @Date: 2023/2/8 10:50
 * @Desc: 处理服务端逻辑
 */
public class ProcessHandler implements Runnable 
    private Socket socket;

    public ProcessHandler(Socket socket) 
        this.socket = socket;
    

    @Override
    public void run() 
        ObjectInputStream objectInputStream = null;
        ObjectOutputStream objectOutputStream = null;

        try 
            objectInputStream = new ObjectInputStream(socket.getInputStream());
            RpcRequest rpcRequest = (RpcRequest) objectInputStream.readObject();

            Class clazz = null;
            // 判断是否存在于注册中心中
            if (Registry.containsKey(rpcRequest.getClassName()))
                clazz = Registry.get(rpcRequest.getClassName());
            
            Method method = clazz.getMethod(rpcRequest.getMethodName(), rpcRequest.getTypes());
            Object result = method.invoke(clazz.newInstance(), rpcRequest.getParams());

            // 返回结果
            objectOutputStream = new ObjectOutputStream(socket.getOutputStream());
            objectOutputStream.writeObject(result);
            objectOutputStream.flush();

         catch (IOException e) 
            e.printStackTrace();
         catch (ClassNotFoundException e) 
            e.printStackTrace();
         catch (NoSuchMethodException e) 
            e.printStackTrace();
         catch (InvocationTargetException e) 
            e.printStackTrace();
         catch (IllegalAccessException e) 
            e.printStackTrace();
         catch (InstantiationException e) 
            e.printStackTrace();
        finally 
            try 
                if (objectInputStream !=null)
                    objectInputStream.close();
                
                if (objectOutputStream !=null)
                    objectOutputStream.close();
                
            catch (IOException e)
                e.printStackTrace();
            

        
    

代理

package com.rpc.framework.proxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;

/**
 * @Author: Yangmiao
 * @Date: 2023/2/8 11:18
 * @Desc: 创建动态代理
 */
public class RpcProxy<T> 

    public T remoteCall(String host,int port,Class clazz)
        return (T) Proxy.newProxyInstance(
                clazz.getClassLoader(),
                (Class<?>[]) new Class[]clazz,
                new RemoteInvocationHandler(host,port,clazz)
        );
    

package com.rpc.framework.proxy;

import com.rpc.framework.RpcRequest;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * @Author: Yangmiao
 * @Date: 2023/2/8 11:22
 * @Desc: 代理类执行的逻辑
 */
public class RemoteInvocationHandler implements InvocationHandler 

    private String host;
    private int port;
    private Class clazz;

    public RemoteInvocationHandler(String host,int port,Class clazz)
        this.host = host;
        this.port = port;
        this.clazz = clazz;
    

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable 
        RpcRequest rpcRequest = new RpcRequest();

        rpcRequest.setClassName(clazz.getName());
        rpcRequest.setMethodName(method.getName());
        rpcRequest.setTypes(method.getParameterTypes());
        rpcRequest.setParams(args);

        ObjectOutputStream objectOutputStream = null;
        ObjectInputStream objectInputStream = null;

        try 
            Socket socket = new Socket(host,port);
            // 发送消息
            objectOutputStream = new ObjectOutputStream(socket.getOutputStream());
            objectOutputStream.writeObject(rpcRequest);
            objectOutputStream.flush();

            // 接受结果
            objectInputStream = new ObjectInputStream(socket.getInputStream());
            Object readObject = objectInputStream.readObject();
            return readObject;
        catch (Exception e)
            e.printStackTrace();
        finally 
            try 
                if (objectInputStream !=null)
                    objectInputStream.close();
                
                if (objectOutputStream!=null)
                    objectOutputStream.close();
                
            catch (IOException e)
                e.printStackTrace();
            
        
        return null;
    

测试