gk-rpc
项目模块
- 1 client 客户端
- 2 server 服务
- 3 proto 协议
- 4 codec 编解码
- 5 transport 数据传输
- 6 common 工具
- 7 example 测试样例
1.Proto 模块
Proto模块用于规定数据传输协议和规约，其主要类有3个：
1.1 Request类用于储存某一需要执行方法的method描述（即serviceDescriptor）与实参。
@Data
public class Request {
private ServiceDescriptor serviceDescriptor;
private Object [] parameters;
}
这里的实参将会在client调用方法时通过动态代理获取，并且通过http协议传递到Server进行处理。而在Server中会根据传递的class与实例通过反射进行实际方法的执行，最后将执行结果通过Response类进行返回。
1.2 Reponse类描述如下：
@Data
public class Response {
/**
* 服务返回编码，0-成功 ，非0失败
*/
private int code;//成功与否
/**
* 具体的错误信息
*/
private String message = "ok";
/**
* 返回的数据
*/
private Object data;
}
1.3 ServiceDescriptor类描述如下：
@Data
@AllArgsConstructor
@NoArgsConstructor
public class ServiceDescriptor {
private String clazz;//类名
private String method;//方法名
private String returnType;//返回类型
private String[] parameterTypes;//参数类型
public static ServiceDescriptor from(Class clazz, Method method){
ServiceDescriptor sdp = new ServiceDescriptor();
sdp.setClazz(clazz.getName());
sdp.setMethod(method.getName());
sdp.setReturnType(method.getReturnType().getName());
Class[] parameterClasses = method.getParameterTypes();
String[] parameterTypes = new String[parameterClasses.length];
for(int i =0;i<parameterClasses.length;i++){
parameterTypes[i] = parameterClasses[i].getName();
}
sdp.setParameterTypes(parameterTypes);
return sdp;
}
// ...省略hashcode equals toString
}
该类主要用于存储方法信息，而在Server中会将类映射到对应于该类的具体实例，以便反射执行具体方法。
2 Transport 模块
该模块主要用于client与server的http通信处理问题，其client请求内容以Request类形式封装传输，server响应内容以Reponse类封装返回。
2.1 HTTPTransportClient类实现如下：
public class HTTPTransportClient implements TransportClient{
private String url;
@Override
public void connect(Peer peer) {
this.url="http://"+peer.getHost()+":"+peer.getPort();
}
@Override
public InputStream write(InputStream data) {
try {
HttpURLConnection httpConn = (HttpURLConnection) new URL(url).openConnection();
httpConn.setDoInput(true);
httpConn.setDoOutput(true);
httpConn.setUseCaches(false);
httpConn.setRequestMethod("POST");
httpConn.connect();
IOUtils.copy(data,httpConn.getOutputStream());
int resultCode = httpConn.getResponseCode();
if(resultCode==HttpURLConnection.HTTP_OK){
return httpConn.getInputStream();
}else{
return httpConn.getErrorStream();
}
} catch (IOException e) {
throw new IllegalStateException(e);
}
}
@Override
public void close() {}
}
Peer类为定义在Proto模块中的Server通信地址与端口不做特殊介绍。该类主要方法为write(),主要是用于向server传递数据并且获取响应数据。其最终调用将在RpcClient类中调用。
2.2 HTTPTransportServer 类主要实现如下：
@Slf4j
public class HttpTransportServer implements TransportServer {
private RequestHandler handler;
private Server server;
@Override
public void init(int port, RequestHandler handler) {
this.handler = handler;
this.server = new Server(port);
//servlet 接收请求
ServletContextHandler ctx = new ServletContextHandler();
server.setHandler(ctx);
ServletHolder holder = new ServletHolder(new RequestServlet());
ctx.addServlet(holder,"/*");
}
@Override
public void start() {
try {
server.start();
server.join();
} catch (Exception e) {
log.error(e.getMessage(),e);
}
}
@Override
public void stop() {
try {
server.stop();
} catch (Exception e) {
log.error(e.getMessage(),e);
}
}
class RequestServlet extends HttpServlet{
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
log.info("client connect");
InputStream in =req.getInputStream();
OutputStream out = resp.getOutputStream();
if(handler !=null){
handler.onRequest(in,out);
}
out.flush();
}
}
}
上述类使用Jetty容器完成init(),start(),stop()功能。上述类最重要一个关注点在于RequestHandler实例的初始化，该抽象类定义于Transport模块，主要用于server处理来自client的请求。其抽象方法实现将在RpcServer类中详细讲解。
3 Common 模块
common模块主要为一些反射工具，其具体实现如下:
public class ReflectionUtils {
/**
* 根据class创建对象
*
* @param clazz 待创建兑现骨干的类
* @param <T> 对象类型
* @return 创建好的对象
*/
public static <T> T newInstance(Class<T> clazz) throws IllegalStateException{
try {
return clazz.newInstance();
} catch (Exception e) {
throw new IllegalStateException(e);
}
}
/**
* 获取某个class的共有方法
*
* @param clazz
* @return 当前类声明的共有方法
*/
public static Method[] getPublicMethods(Class clazz) {
Method[] methods = clazz.getDeclaredMethods();
List<Method> pmethods = new ArrayList<>();
for (Method m : methods) {
if (Modifier.isPublic(m.getModifiers())) {
pmethods.add(m);
}
}
return pmethods.toArray(new Method[0]);
}
/**
* 调用指定对象的方法
*
* @param obj 被调用的对象
* @param method 被调用的方法
* @param args 方法的参数
* @return 返回结果
*/
public static Object invoke(Object obj, Method method, Object... args) throws IllegalStateException{
try {
return method.invoke(obj, args);
} catch (Exception e) {
throw new IllegalStateException(e);
}
}
}
上述getPublicMethods()方法一个用途是Server注册时存储所有的method的ServcieSescriptor。invoke()方法用于执行指定实例对象的method。
4 Server 模块
本项目最核心两个模块之一，主要作用是定义了处理client请求的方法。
4.1 RpcServer类实现如下：
@Slf4j
public class RpcServer {
private RPCServerConfig config;
private TransportServer net;
private Encoder encoder;
private Decoder decoder;
private ServiceManager serviceManager;
private ServiceInvoker serviceInvoker;
public RpcServer() {
}
public RpcServer(RPCServerConfig config) {
this.config = config;
//net
this.net = ReflectionUtils.newInstance(config.getTransportClass());
this.net.init(config.getPort(),this.handler);
//codec
this.encoder = ReflectionUtils.newInstance(config.getEncoderClass());
this.decoder = ReflectionUtils.newInstance(config.getDecoderClass());
//service
this.serviceManager = new ServiceManager();
this.serviceInvoker = new ServiceInvoker();
}
public <T> void register(Class<T> interfaceClasss,T bean){
serviceManager.register(interfaceClasss,bean);
}
public void start(){
this.net.start();
}
public void stop(){
this.net.stop();
}
private RequestHandler handler = new RequestHandler() {
@Override
public void onRequest(InputStream recive, OutputStream toResp) {
Response resp = new Response();
try {
byte[] inBytes = new byte[recive.available()];
IOUtils.readFully(recive,inBytes,0,recive.available());
// byte[] inBytes = IOUtils.readFully(recive,recive.available());
Request request = decoder.decode(inBytes,Request.class);//这里是从client传过来的
log.info("get request: {}",request);
ServiceInstance sis = serviceManager.lookup(request );//request封装了ServiceDescriptor描述字符串
Object ret = serviceInvoker.invoke(sis,request);//执行返回结果
resp.setData(ret);
} catch (Exception e) {
log.warn(e.getMessage(),e);
resp.setCode(1);
resp.setMessage("RpcServer got error"+e.getClass().getName()+" : "+e.getMessage());
}finally {
try {
byte[] outBytes = encoder.encode(resp);
toResp.write(outBytes);
log.info("response client");
} catch (IOException e) {
log.warn(e.getMessage(),e);
}
}
}
};
}
该方法初时较复杂，理清各个类之后将比较明了。上述RpcServerConfig主要用于常量配置的定义，Encoder与Decoder分别为编码器与解码器不做过多解释。
ServiceManager类的实现如下:
@Slf4j
public class ServiceManager {
private Map<ServiceDescriptor,ServiceInstance> services;
public ServiceManager(){
this.services = new ConcurrentHashMap<>();
}
public <T> void register(Class<T> interfaceClass, T bean){
Method[] methods = ReflectionUtils.getPublicMethods(interfaceClass);
for (Method method :methods){
ServiceInstance sis = new ServiceInstance(bean,method);
ServiceDescriptor sdp = ServiceDescriptor.from(interfaceClass,method);
services.put(sdp,sis);
log.info("register service {} {}",sdp.getClazz(),sdp.getMethod());
}
}
public ServiceInstance lookup(Request request){
ServiceDescriptor sdp = request.getServiceDescriptor();
return services.get(sdp);
}
}
register()方法主要用于注册该class的所有共有方法，并且获取之前讲述的ServiceDescriptor实例与ServiceInstance作为键值对的形式存储。**（需要注意的是这里的registetr方法的参数bean正是需要执行的实例对象）**其ServiceInstance类的定义如下：
@Data
@AllArgsConstructor
public class ServiceInstance {
private Object target;
private Method method;
}
其内部主要定义了连个变量，一个是需要执行某个method的目标对象，另一个是需要执行的method。（到这里应该认识了ServiceManager的真正作用，存储method的描述与实例的对应关系，方便通过client的传参进行get）
回到上述初始类RpcServer，最需要注意的是RequestHandler的实现。其onRequest()方法通过Servlet的inputStream与OutputStream参数获取来自Client的数据，并且通过获取到的Request实例参数从ServiceManager中get实例对象与method。因为Request对象中包含有Client获取到的实际参数，因此将上述参数一起传递到ServiceInvoker对象进行执行。该类实现如下：
public class ServiceInvoker {
public Object invoke(ServiceInstance service, Request request){
return ReflectionUtils.invoke(service.getTarget(),service.getMethod(),request.getParameters());
}
}
上述代码最终只是调用common模块的反射工具封装执行。
5 Client 模块
该模块主要功能有连个一个时动态代理获取实参，一个是请求Server进行过程调用。
其RpcClient类实现如下：
public class RpcClient {
private RpcClientConfig config;
private Encoder encoder;
private Decoder decoder;
private TransportSelector selector;
public RpcClient(RpcClientConfig config) {
this.config = config;
this.encoder = ReflectionUtils.newInstance(this.config.getEncoderClass());
this.decoder = ReflectionUtils.newInstance(this.config.getDecoderClass());
this.selector = ReflectionUtils.newInstance(this.config.getSelectorClass());
this.selector.init(this.config.getServers(),
this.config.getConnectCount(),
this.config.getTransportClass());
}
public RpcClient() {
this(new RpcClientConfig());
}
public <T> T getProxy(Class<T> clazz){
return (T)Proxy.newProxyInstance(
getClass().getClassLoader(),
new Class[]{clazz},
new RemoteInvoker(clazz,encoder,decoder,selector)
);
}
}
该类需要注意两点，之一是TransportSelector对象，其实现如下：
@Slf4j
public class RandomTransportSelector implements TransportSelector {
/**
* 已经连接好的client
*/
private List<TransportClient> clients;
public RandomTransportSelector() {
clients = new ArrayList<>();
}
@Override
public synchronized void init(List<Peer> peers, int count, Class<? extends TransportClient> clazz) {
count = Math.max(count,1);
for (Peer peer : peers){
for (int i =0;i<count;i++){
TransportClient client = ReflectionUtils.newInstance(clazz);
client.connect(peer);
clients.add(client);
}
log.info("connect server: {} ",peer);
}
}
@Override
public synchronized TransportClient select() {
int i = new Random().nextInt(clients.size());
return clients.remove(i);
}
@Override
public synchronized void release(TransportClient client) {
clients.add(client);
}
@Override
public synchronized void close() {
for (TransportClient client :clients){
client.close();
}
clients.clear();
}
}
该类主要是用于处理Client对Server的连接问题，相当于连接池，由有需求时随机返回连接。 回到上述RpcClient类的getProxy()方法为动态代理，不为此介绍的重点，但是需要重点关注RemoteInvoker类，实现如下：
Slf4j
public class RemoteInvoker implements InvocationHandler{
private Class clazz;
private Encoder encoder;
private Decoder decoder;
private TransportSelector selector;
public RemoteInvoker(Class clazz , Encoder encoder, Decoder decoder, TransportSelector selector) {
this.clazz = clazz;
this.decoder = decoder;
this.encoder = encoder;
this.selector = selector;
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
Request request = new Request();
request.setServiceDescriptor(ServiceDescriptor.from(clazz,method));
request.setParameters(args);
Response response = invokeRemote(request);
if(response==null || response.getCode()!=0){
throw new IllegalStateException("fail to invoke remote: "+response);
}
return response.getData();
}
private Response invokeRemote(Request request){
TransportClient client = null;
Response response = null;
try{
client = selector.select();
byte[] outBytes = encoder.encode(request);
InputStream revice = client.write(new ByteArrayInputStream(outBytes));
byte[] inBytes = new byte[revice.available()];
IOUtils.readFully(revice,inBytes,0,revice.available());
// byte[] inBytes = IOUtils.readFully(revice , revice.available());
response = decoder.decode(inBytes,Response.class);
}catch (IOException e) {
log.warn(e.getMessage(),e);
response = new Response();
response.setCode(1);
response.setMessage("RpcClient got error:"+e.getClass()+" : "+e.getMessage());
}finally {
if(client!=null){
selector.release(client);
}
}
return response;
}
}
上述代码需要关注invoke()方法中对代理方法的参数进行存储封装到Request对象并且最终序列化传递到Server。至此本项目个关键模块实现与执行流程介绍完毕。
下一步
- 线程池
- 注册中心
- 数据安全传输
- 流行框架集成