前言
在微服務大行其道的今天,分佈式系統越來越重要,實現服務化首先就要考慮服務之間的通信問題。這裏面涉及序列化、反序列化、尋址、連接等等問題。。不過,有了RPC框架,我們就無需苦惱。
一、什麼是RPC?
RPC(Remote Procedure Call)— 遠程過程調用,是一個計算機通信協議。該協議允許運行於一臺計算機的程序調用另一臺計算機的子程序,而程序員無需額外地爲這個交互作用編程。
值得注意是,兩個或多個應用程序都分佈在不同的服務器上,它們之間的調用都像是本地方法調用一樣。
RPC框架有很多,比較知名的如阿里的Dubbo、google的gRPC、Go語言的rpcx、Apache的thrift。當然了,還有Spring Cloud,不過對於Spring Cloud來說,RPC只是它的一個功能模塊。
複雜的先不講,如果要實現一個基本功能、簡單的RPC,要涉及哪些東西呢?
- 動態代理
- 反射
- 序列化、反序列化
- 網絡通信
- 編解碼
- 服務發現和註冊
- 心跳與鏈路檢測
- …
下面我們一起通過代碼來分析,怎麼把這些技術點串到一起,實現我們自己的RPC。
二、環境準備
在開始之前,筆者先介紹一下所用到的軟件環境。
SpringBoot、Netty、zookeeper、zkclient、fastjson
- SpringBoot
項目的基礎框架,方便打成JAR包,便於測試。 - Netty
通信服務器 - zookeeper
服務的發現與註冊 - zkclient
zookeeper客戶端 - fastjson
序列化、反序列化
三、RPC生產者
1、服務接口API
整個RPC,我們分爲生產者和消費者。首先它們有一個共同的服務接口API。在這裏,我們搞一個操作用戶信息的service接口。
public interface InfoUserService {
List<InfoUser> insertInfoUser(InfoUser infoUser);
InfoUser getInfoUserById(String id);
void deleteInfoUserById(String id);
String getNameById(String id);
Map<String,InfoUser> getAllUser();
}
2、服務類實現
作爲生產者,它當然要有實現類,我們創建InfoUserServiceImpl實現類,並用註解把它標註爲RPC的服務,然後註冊到Spring的Bean容器中。在這裏,我們把infoUserMap當做數據庫,存儲用戶信息。
package com.viewscenes.netsupervisor.service.impl;
@RpcService
public class InfoUserServiceImpl implements InfoUserService {
Logger logger = LoggerFactory.getLogger(this.getClass());
//當做數據庫,存儲用戶信息
Map<String,InfoUser> infoUserMap = new HashMap<>();
public List<InfoUser> insertInfoUser(InfoUser infoUser) {
logger.info("新增用戶信息:{}", JSONObject.toJSONString(infoUser));
infoUserMap.put(infoUser.getId(),infoUser);
return getInfoUserList();
}
public InfoUser getInfoUserById(String id) {
InfoUser infoUser = infoUserMap.get(id);
logger.info("查詢用戶ID:{}",id);
return infoUser;
}
public List<InfoUser> getInfoUserList() {
List<InfoUser> userList = new ArrayList<>();
Iterator<Map.Entry<String, InfoUser>> iterator = infoUserMap.entrySet().iterator();
while (iterator.hasNext()){
Map.Entry<String, InfoUser> next = iterator.next();
userList.add(next.getValue());
}
logger.info("返回用戶信息記錄數:{}",userList.size());
return userList;
}
public void deleteInfoUserById(String id) {
logger.info("刪除用戶信息:{}",JSONObject.toJSONString(infoUserMap.remove(id)));
}
public String getNameById(String id){
logger.info("根據ID查詢用戶名稱:{}",id);
return infoUserMap.get(id).getName();
}
public Map<String,InfoUser> getAllUser(){
logger.info("查詢所有用戶信息{}",infoUserMap.keySet().size());
return infoUserMap;
}
}
元註解定義如下:
package com.viewscenes.netsupervisor.annotation;
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Component
public @interface RpcService {}
3、請求信息和返回信息
所有的請求信息和返回信息,我們用兩個JavaBean來表示。其中的重點是,返回信息要帶有請求信息的ID。
package com.viewscenes.netsupervisor.entity;
public class Request {
private String id;
private String className;// 類名
private String methodName;// 函數名稱
private Class<?>[] parameterTypes;// 參數類型
private Object[] parameters;// 參數列表
get/set ...
}
package com.viewscenes.netsupervisor.entity;
public class Response {
private String requestId;
private int code;
private String error_msg;
private Object data;
get/set ...
}
4、Netty服務端
Netty作爲高性能的NIO通信框架,在很多RPC框架中都有它的身影。我們也採用它當做通信服務器。說到這,我們先看個配置文件,重點有兩個,zookeeper的註冊地址和Netty通信服務器的地址。
TOMCAT端口
server.port=8001
#zookeeper註冊地址
registry.address=192.168.245.131:2181,192.168.245.131:2182,192.168.245.131:2183
#RPC服務提供者地址
rpc.server.address=192.168.197.1:18868
爲了方便管理,我們把它也註冊成Bean,同時實現ApplicationContextAware接口,把上面@RpcService註解的服務類撈出來,緩存起來,供消費者調用。同時,作爲服務器,還要對客戶端的鏈路進行心跳檢測,超過60秒未讀寫數據,關閉此連接。
package com.viewscenes.netsupervisor.netty.server;
@Component
public class NettyServer implements ApplicationContextAware,InitializingBean{
private static final Logger logger = LoggerFactory.getLogger(NettyServer.class);
private static final EventLoopGroup bossGroup = new NioEventLoopGroup(1);
private static final EventLoopGroup workerGroup = new NioEventLoopGroup(4);
private Map<String, Object> serviceMap = new HashMap<>();
@Value("${rpc.server.address}")
private String serverAddress;
@Autowired
ServiceRegistry registry;
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
Map<String, Object> beans = applicationContext.getBeansWithAnnotation(RpcService.class);
for(Object serviceBean:beans.values()){
Class<?> clazz = serviceBean.getClass();
Class<?>[] interfaces = clazz.getInterfaces();
for (Class<?> inter : interfaces){
String interfaceName = inter.getName();
logger.info("加載服務類: {}", interfaceName);
serviceMap.put(interfaceName, serviceBean);
}
}
logger.info("已加載全部服務接口:{}", serviceMap);
}
public void afterPropertiesSet() throws Exception {
start();
}
public void start(){
final NettyServerHandler handler = new NettyServerHandler(serviceMap);
new Thread(() -> {
try {
ServerBootstrap bootstrap = new ServerBootstrap();
bootstrap.group(bossGroup,workerGroup).
channel(NioServerSocketChannel.class).
option(ChannelOption.SO_BACKLOG,1024).
childOption(ChannelOption.SO_KEEPALIVE,true).
childOption(ChannelOption.TCP_NODELAY,true).
childHandler(new ChannelInitializer<SocketChannel>() {
//創建NIOSocketChannel成功後,在進行初始化時,將它的ChannelHandler設置到ChannelPipeline中,用於處理網絡IO事件
protected void initChannel(SocketChannel channel) throws Exception {
ChannelPipeline pipeline = channel.pipeline();
pipeline.addLast(new IdleStateHandler(0, 0, 60));
pipeline.addLast(new JSONEncoder());
pipeline.addLast(new JSONDecoder());
pipeline.addLast(handler);
}
});
String[] array = serverAddress.split(":");
String host = array[0];
int port = Integer.parseInt(array[1]);
ChannelFuture cf = bootstrap.bind(host,port).sync();
logger.info("RPC 服務器啓動.監聽端口:"+port);
registry.register(serverAddress);
//等待服務端監聽端口關閉
cf.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}).start();
}
}
上面的代碼就把Netty服務器啓動了,在處理器中的構造函數中,我們先把服務Bean的Map傳進來,所有的處理要基於這個Map才能找到對應的實現類。在channelRead中,獲取請求方法的信息,然後通過反射調用方法獲取返回值。
package com.viewscenes.netsupervisor.netty.server;
@ChannelHandler.Sharable
public class NettyServerHandler extends ChannelInboundHandlerAdapter {
private final Logger logger = LoggerFactory.getLogger(NettyServerHandler.class);
private final Map<String, Object> serviceMap;
public NettyServerHandler(Map<String, Object> serviceMap) {
this.serviceMap = serviceMap;
}
public void channelActive(ChannelHandlerContext ctx) {
logger.info("客戶端連接成功!"+ctx.channel().remoteAddress());
}
public void channelInactive(ChannelHandlerContext ctx) {
logger.info("客戶端斷開連接!{}",ctx.channel().remoteAddress());
ctx.channel().close();
}
public void channelRead(ChannelHandlerContext ctx, Object msg) {
Request request = JSON.parseObject(msg.toString(),Request.class);
if ("heartBeat".equals(request.getMethodName())) {
logger.info("客戶端心跳信息..."+ctx.channel().remoteAddress());
}else{
logger.info("RPC客戶端請求接口:"+request.getClassName()+" 方法名:"+request.getMethodName());
Response response = new Response();
response.setRequestId(request.getId());
try {
Object result = this.handler(request);
response.setData(result);
} catch (Throwable e) {
e.printStackTrace();
response.setCode(1);
response.setError_msg(e.toString());
logger.error("RPC Server handle request error",e);
}
ctx.writeAndFlush(response);
}
}
/**
* 通過反射,執行本地方法
* @param request
* @return
* @throws Throwable
*/
private Object handler(Request request) throws Throwable{
String className = request.getClassName();
Object serviceBean = serviceMap.get(className);
if (serviceBean!=null){
Class<?> serviceClass = serviceBean.getClass();
String methodName = request.getMethodName();
Class<?>[] parameterTypes = request.getParameterTypes();
Object[] parameters = request.getParameters();
Method method = serviceClass.getMethod(methodName, parameterTypes);
method.setAccessible(true);
return method.invoke(serviceBean, getParameters(parameterTypes,parameters));
}else{
throw new Exception("未找到服務接口,請檢查配置!:"+className+"#"+request.getMethodName());
}
}
/**
* 獲取參數列表
* @param parameterTypes
* @param parameters
* @return
*/
private Object[] getParameters(Class<?>[] parameterTypes,Object[] parameters){
if (parameters==null || parameters.length==0){
return parameters;
}else{
Object[] new_parameters = new Object[parameters.length];
for(int i=0;i<parameters.length;i++){
new_parameters[i] = JSON.parseObject(parameters[i].toString(),parameterTypes[i]);
}
return new_parameters;
}
}
public void userEventTriggered(ChannelHandlerContext ctx, Object evt)throws Exception {
if (evt instanceof IdleStateEvent){
IdleStateEvent event = (IdleStateEvent)evt;
if (event.state()== IdleState.ALL_IDLE){
logger.info("客戶端已超過60秒未讀寫數據,關閉連接.{}",ctx.channel().remoteAddress());
ctx.channel().close();
}
}else{
super.userEventTriggered(ctx,evt);
}
}
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
logger.info(cause.getMessage());
ctx.close();
}
}
4、服務註冊
我們啓動了Netty通信服務器,並且把服務實現類加載到緩存,等待請求時調用。這一步,我們要進行服務註冊。爲了簡單化處理,我們只註冊通信服務器的監聽地址即可。
在上面代碼中,bind之後我們執行了registry.register(serverAddress);
它的作用就是,將Netty監聽的IP端口註冊到zookeeper。
package com.viewscenes.netsupervisor.registry;
@Component
public class ServiceRegistry {
Logger logger = LoggerFactory.getLogger(this.getClass());
@Value("${registry.address}")
private String registryAddress;
private static final String ZK_REGISTRY_PATH = "/rpc";
public void register(String data) {
if (data != null) {
ZkClient client = connectServer();
if (client != null) {
AddRootNode(client);
createNode(client, data);
}
}
}
//連接zookeeper
private ZkClient connectServer() {
ZkClient client = new ZkClient(registryAddress,20000,20000);
return client;
}
//創建根目錄/rpc
private void AddRootNode(ZkClient client){
boolean exists = client.exists(ZK_REGISTRY_PATH);
if (!exists){
client.createPersistent(ZK_REGISTRY_PATH);
logger.info("創建zookeeper主節點 {}",ZK_REGISTRY_PATH);
}
}
//在/rpc根目錄下,創建臨時順序子節點
private void createNode(ZkClient client, String data) {
String path = client.create(ZK_REGISTRY_PATH + "/provider", data, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);
logger.info("創建zookeeper數據節點 ({} => {})", path, data);
}
}
有一點需要注意,子節點必須是臨時節點。這樣,生產者端停掉之後,才能通知到消費者,把此服務從服務列表中剔除。到此爲止,生產者端已經完成。我們看一下它的啓動日誌:
加載服務類: com.viewscenes.netsupervisor.service.InfoUserService
已加載全部服務接口:{com.viewscenes.netsupervisor.service.InfoUserService=com.viewscenes.netsupervisor.service.impl.InfoUserServiceImpl@46cc127b}
Initializing ExecutorService 'applicationTaskExecutor'
Tomcat started on port(s): 8001 (http) with context path ''
Started RpcProviderApplication in 2.003 seconds (JVM running for 3.1)
RPC 服務器啓動.監聽端口:18868
Starting ZkClient event thread.
Socket connection established to 192.168.245.131/192.168.245.131:2183, initiating session
Session establishment complete on server 192.168.245.131/192.168.245.131:2183, sessionid = 0x367835b48970010, negotiated timeout = 4000
zookeeper state changed (SyncConnected)
創建zookeeper主節點 /rpc
創建zookeeper數據節點 (/rpc/provider0000000000 => 192.168.197.1:28868)
四、RPC消費者
首先,我們需要把生產者端的服務接口API,即InfoUserService。以相同的目錄放到消費者端。路徑不同,調用會找不到的哦。
1、代理
RPC的目標其中有一條,《程序員無需額外地爲這個交互作用編程。》所以,我們在調用的時候,就像調用本地方法一樣。就像下面這樣:
@Controller
public class IndexController {
@Autowired
InfoUserService userService;
@RequestMapping("getById")
@ResponseBody
public InfoUser getById(String id){
logger.info("根據ID查詢用戶信息:{}",id);
return userService.getInfoUserById(id);
}
}
那麼,問題來了。消費者端並沒有此接口的實現,怎麼調用到的呢?這裏,首先就是代理。筆者這裏用的是Spring的工廠Bean機制創建的代理對象,涉及的代碼較多,就不在文章中體現了,如果有不懂的同學,請想象一下,MyBatis中的Mapper接口怎麼被調用的。可以參考筆者文章:Mybatis源碼分析(四)mapper接口方法是怎樣被調用到的
總之,在調用userService方法的時候,會調用到代理對象的invoke方法。在這裏,封裝請求信息,然後調用Netty的客戶端方法發送消息。然後根據方法返回值類型,轉成相應的對象返回。
package com.viewscenes.netsupervisor.configurer.rpc;
@Component
public class RpcFactory<T> implements InvocationHandler {
@Autowired
NettyClient client;
Logger logger = LoggerFactory.getLogger(this.getClass());
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
Request request = new Request();
request.setClassName(method.getDeclaringClass().getName());
request.setMethodName(method.getName());
request.setParameters(args);
request.setParameterTypes(method.getParameterTypes());
request.setId(IdUtil.getId());
Object result = client.send(request);
Class<?> returnType = method.getReturnType();
Response response = JSON.parseObject(result.toString(), Response.class);
if (response.getCode()==1){
throw new Exception(response.getError_msg());
}
if (returnType.isPrimitive() || String.class.isAssignableFrom(returnType)){
return response.getData();
}else if (Collection.class.isAssignableFrom(returnType)){
return JSONArray.parseArray(response.getData().toString(),Object.class);
}else if(Map.class.isAssignableFrom(returnType)){
return JSON.parseObject(response.getData().toString(),Map.class);
}else{
Object data = response.getData();
return JSONObject.parseObject(data.toString(), returnType);
}
}
}
2、服務發現
在生產者端,我們把服務IP端口都註冊到zookeeper中,所以這裏,我們要去拿到服務地址,然後通過Netty連接。重要的是,還要對根目錄進行監聽子節點變化,這樣隨着生產者的上線和下線,消費者端可以及時感知。
package com.viewscenes.netsupervisor.connection;
@Component
public class ServiceDiscovery {
@Value("${registry.address}")
private String registryAddress;
@Autowired
ConnectManage connectManage;
// 服務地址列表
private volatile List<String> addressList = new ArrayList<>();
private static final String ZK_REGISTRY_PATH = "/rpc";
private ZkClient client;
Logger logger = LoggerFactory.getLogger(this.getClass());
@PostConstruct
public void init(){
client = connectServer();
if (client != null) {
watchNode(client);
}
}
//連接zookeeper
private ZkClient connectServer() {
ZkClient client = new ZkClient(registryAddress,30000,30000);
return client;
}
//監聽子節點數據變化
private void watchNode(final ZkClient client) {
List<String> nodeList = client.subscribeChildChanges(ZK_REGISTRY_PATH, (s, nodes) -> {
logger.info("監聽到子節點數據變化{}",JSONObject.toJSONString(nodes));
addressList.clear();
getNodeData(nodes);
updateConnectedServer();
});
getNodeData(nodeList);
logger.info("已發現服務列表...{}", JSONObject.toJSONString(addressList));
updateConnectedServer();
}
//連接生產者端服務
private void updateConnectedServer(){
connectManage.updateConnectServer(addressList);
}
private void getNodeData(List<String> nodes){
logger.info("/rpc子節點數據爲:{}", JSONObject.toJSONString(nodes));
for(String node:nodes){
String address = client.readData(ZK_REGISTRY_PATH+"/"+node);
addressList.add(address);
}
}
}
其中,connectManage.updateConnectServer(addressList);
就是根據服務地址,去連接生產者端的Netty服務。然後創建一個Channel列表,在發送消息的時候,從中選取一個Channel和生產者端進行通信。
3、Netty客戶端
Netty客戶端有兩個方法比較重要,一個是根據IP端口連接服務器,返回Channel,加入到連接管理器;一個是用Channel發送請求數據。同時,作爲客戶端,空閒的時候還要往服務端發送心跳信息。
package com.viewscenes.netsupervisor.netty.client;
@Component
public class NettyClient {
Logger logger = LoggerFactory.getLogger(this.getClass());
private EventLoopGroup group = new NioEventLoopGroup(1);
private Bootstrap bootstrap = new Bootstrap();
@Autowired
NettyClientHandler clientHandler;
@Autowired
ConnectManage connectManage;
public Object send(Request request) throws InterruptedException{
Channel channel = connectManage.chooseChannel();
if (channel!=null && channel.isActive()) {
SynchronousQueue<Object> queue = clientHandler.sendRequest(request,channel);
Object result = queue.take();
return JSONArray.toJSONString(result);
}else{
Response res = new Response();
res.setCode(1);
res.setError_msg("未正確連接到服務器.請檢查相關配置信息!");
return JSONArray.toJSONString(res);
}
}
public Channel doConnect(SocketAddress address) throws InterruptedException {
ChannelFuture future = bootstrap.connect(address);
Channel channel = future.sync().channel();
return channel;
}
....其他方法略
}
我們必須重點關注send方法,它是在代理對象invoke方法調用到的。首先從連接器中輪詢選擇一個Channel,然後發送數據。但是,Netty是異步操作,我們還要轉爲同步,就是說要等待生產者端返回數據才往下執行。筆者在這裏用的是同步隊列SynchronousQueue,它的take方法會阻塞在這裏,直到裏面有數據可讀。然後在處理器中,拿到返回信息寫到隊列中,take方法返回。
package com.viewscenes.netsupervisor.netty.client;
@Component
@ChannelHandler.Sharable
public class NettyClientHandler extends ChannelInboundHandlerAdapter {
@Autowired
NettyClient client;
@Autowired
ConnectManage connectManage;
Logger logger = LoggerFactory.getLogger(this.getClass());
private ConcurrentHashMap<String,SynchronousQueue<Object>> queueMap = new ConcurrentHashMap<>();
public void channelActive(ChannelHandlerContext ctx) {
logger.info("已連接到RPC服務器.{}",ctx.channel().remoteAddress());
}
public void channelInactive(ChannelHandlerContext ctx) {
InetSocketAddress address =(InetSocketAddress) ctx.channel().remoteAddress();
logger.info("與RPC服務器斷開連接."+address);
ctx.channel().close();
connectManage.removeChannel(ctx.channel());
}
public void channelRead(ChannelHandlerContext ctx, Object msg)throws Exception {
Response response = JSON.parseObject(msg.toString(),Response.class);
String requestId = response.getRequestId();
SynchronousQueue<Object> queue = queueMap.get(requestId);
queue.put(response);
queueMap.remove(requestId);
}
public SynchronousQueue<Object> sendRequest(Request request,Channel channel) {
SynchronousQueue<Object> queue = new SynchronousQueue<>();
queueMap.put(request.getId(), queue);
channel.writeAndFlush(request);
return queue;
}
public void userEventTriggered(ChannelHandlerContext ctx, Object evt)throws Exception {
logger.info("已超過30秒未與RPC服務器進行讀寫操作!將發送心跳消息...");
if (evt instanceof IdleStateEvent){
IdleStateEvent event = (IdleStateEvent)evt;
if (event.state()== IdleState.ALL_IDLE){
Request request = new Request();
request.setMethodName("heartBeat");
ctx.channel().writeAndFlush(request);
}
}else{
super.userEventTriggered(ctx,evt);
}
}
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause){
logger.info("RPC通信服務器發生異常.{}",cause);
ctx.channel().close();
}
}
至此,消費者端也基本完成。同樣的,我們先看一下啓動日誌:
Waiting for keeper state SyncConnected
Opening socket connection to server 192.168.139.129/192.168.139.129:2181. Will not attempt to authenticate using SASL (unknown error)
Socket connection established to 192.168.139.129/192.168.139.129:2181, initiating session
Session establishment complete on server 192.168.139.129/192.168.139.129:2181, sessionid = 0x100000273ba002c, negotiated timeout = 20000
zookeeper state changed (SyncConnected)
/rpc子節點數據爲:["provider0000000015"]
已發現服務列表...["192.168.100.74:18868"]
加入Channel到連接管理器./192.168.100.74:18868
已連接到RPC服務器./192.168.100.74:18868
Initializing ExecutorService 'applicationTaskExecutor'
Tomcat started on port(s): 7002 (http) with context path ''
Started RpcConsumerApplication in 4.218 seconds (JVM running for 5.569)
五、測試
我們以Controller裏面的兩個方法爲例,先開啓100個線程調用insertInfoUser方法,然後開啓1000個線程調用查詢方法getAllUser。
public class IndexController {
Logger logger = LoggerFactory.getLogger(this.getClass());
@Autowired
InfoUserService userService;
@RequestMapping("insert")
@ResponseBody
public List<InfoUser> getUserList() throws InterruptedException {
long start = System.currentTimeMillis();
int thread_count = 100;
CountDownLatch countDownLatch = new CountDownLatch(thread_count);
for (int i=0;i<thread_count;i++){
new Thread(() -> {
InfoUser infoUser = new InfoUser(IdUtil.getId(),"Jeen","BeiJing");
List<InfoUser> users = userService.insertInfoUser(infoUser);
logger.info("返回用戶信息記錄:{}", JSON.toJSONString(users));
countDownLatch.countDown();
}).start();
}
countDownLatch.await();
long end = System.currentTimeMillis();
logger.info("線程數:{},執行時間:{}",thread_count,(end-start));
return null;
}
@RequestMapping("getAllUser")
@ResponseBody
public Map<String,InfoUser> getAllUser() throws InterruptedException {
long start = System.currentTimeMillis();
int thread_count = 1000;
CountDownLatch countDownLatch = new CountDownLatch(thread_count);
for (int i=0;i<thread_count;i++){
new Thread(() -> {
Map<String, InfoUser> allUser = userService.getAllUser();
logger.info("查詢所有用戶信息:{}",JSONObject.toJSONString(allUser));
countDownLatch.countDown();
}).start();
}
countDownLatch.await();
long end = System.currentTimeMillis();
logger.info("線程數:{},執行時間:{}",thread_count,(end-start));
return null;
}
}
結果如下:
六、總結
本文簡單介紹了RPC的整個流程,如果你正在學習RPC的相關知識,可以根據文中的例子,自己實現一遍。相信寫完之後,你會對RPC會有更深一些的認識。
生產者端流程:
- 加載服務,並緩存
- 啓動通訊服務器(Netty)
- 服務註冊(把通訊地址放入zookeeper,也可以把加載到的服務也放進去)
- 反射,本地調用
消費者端流程:
- 代理服務接口
- 服務發現(連接zookeeper,拿到服務地址列表)
- 遠程調用(輪詢生產者服務列表,發送消息)
限於篇幅,本文代碼並不完整,如有需要,訪問:https://github.com/taoxun/simple_rpc 或者添加筆者微信公衆號:<清幽之地的博客>),獲取完整項目。