实现java RPC框架

主要利用socket通信，反射，代理实现类似RMI的RPC框架

首先是框架的代码

package framework;

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;

/**
* RpcFramework
*
* @author william.liangf
*/
public class RpcFramework {

/**
* 暴露服务
*
* @param service 服务实现
* @param port 服务端口
* @throws Exception
*/
public static void export(final Object service, int port) throws Exception {
if (service == null)
throw new IllegalArgumentException("service instance == null");
if (port <= 0 || port > 65535)
throw new IllegalArgumentException("Invalid port " + port);
System.out.println("Export service " + service.getClass().getName() + " on port " + port);
ServerSocket server = new ServerSocket(port);
for(;;) {
try {
final Socket socket = server.accept();//服务器端一旦收到消息，就创建一个线程进行处理
new Thread(new Runnable() {
@Override
public void run() {
try {
try {
ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
try {
String methodName = input.readUTF();//service是服务器端提供服务的对象，但是，要通过获取到的调用方法的名称，参数类型，以及参数来选择对象的方法，并调用。获得方法的名称
Class<?>[] parameterTypes = (Class<?>[])input.readObject();//获得参数的类型
Object[] arguments = (Object[])input.readObject();//获得参数
ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
try {
Method method = service.getClass().getMethod(methodName, parameterTypes);//通过反射机制获得方法
Object result = method.invoke(service, arguments);//通过反射机制获得类的方法，并调用这个方法
output.writeObject(result);//将结果发送
} catch (Throwable t) {
output.writeObject(t);
} finally {
output.close();
}
} finally {
input.close();
}
} finally {
socket.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}).start();
} catch (Exception e) {
e.printStackTrace();
}
}
}

/**
* 引用服务
*
* @param <T> 接口泛型
* @param interfaceClass 接口类型
* @param host 服务器主机名
* @param port 服务器端口
* @return 远程服务
* @throws Exception
*///原理是通过代理，获得服务器端接口的一个“代理”的对象。对这个对象的所有操作都会调用invoke函数，在invoke函数中，是将被调用的函数名，参数列表和参数发送到服务器，并接收服务器处理的结果
@SuppressWarnings("unchecked")
public static <T> T refer(final Class<T> interfaceClass, final String host, final int port) throws Exception {
if (interfaceClass == null)
throw new IllegalArgumentException("Interface class == null");
if (! interfaceClass.isInterface())
throw new IllegalArgumentException("The " + interfaceClass.getName() + " must be interface class!");
if (host == null || host.length() == 0)
throw new IllegalArgumentException("Host == null!");
if (port <= 0 || port > 65535)
throw new IllegalArgumentException("Invalid port " + port);
System.out.println("Get remote service " + interfaceClass.getName() + " from server " + host + ":" + port);
return (T) Proxy.newProxyInstance(interfaceClass.getClassLoader(), new Class<?>[] {interfaceClass}, new InvocationHandler() {
public Object invoke(Object proxy, Method method, Object[] arguments) throws Throwable {
Socket socket = new Socket(host, port);
try {
ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
try {
output.writeUTF(method.getName());
output.writeObject(method.getParameterTypes());
output.writeObject(arguments);
ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
try {
Object result = input.readObject();
if (result instanceof Throwable) {
throw (Throwable) result;
}
return result;
} finally {
input.close();
}
} finally {
output.close();
}
} finally {
socket.close();
}
}
});
}

}


服务接口
package user;

public interface HelloService {
String hello(String name);
}

实现服务
package user;

public class HelloServiceImpl implements HelloService{
public String hello(String name) {
return "Hello " + name;
}

}

服务器
package user;
import framework.RpcFramework;

public class Server {
public static void main(String []args) throws Exception {
HelloService service = new HelloServiceImpl();
RpcFramework.export(service, 1234);
}
}


客户机
package user;
import framework.RpcFramework;

public class Client {
public static void main(String[] args) throws Exception {
HelloService service = RpcFramework.refer(HelloService.class, "127.0.0.1", 1234);
for (int i = 0; i < Integer.MAX_VALUE; i ++) {
String hello = service.hello("World" + i);
System.out.println(hello);
Thread.sleep(1000);
}
}
}