基于Netty4手把手实现一个带注册中心和注解的Dubbo框架

阅读这篇文章之前，建议先阅读和这篇文章关联的内容。

1. 详细剖析分布式微服务架构下网络通信的底层实现原理（图解）

2. (年薪60W的技巧)工作了5年，你真的理解Netty以及为什么要用吗？（深度干货）

3. 深度解析Netty中的核心组件（图解+实例）

4. BAT面试必问细节：关于Netty中的ByteBuf详解

5. 通过大量实战案例分解Netty中是如何解决拆包黏包问题的?

6. 基于Netty实现自定义消息通信协议（协议设计及解析应用实战）

7. 全网最详细最齐全的序列化技术及深度解析与应用实战

8. 手把手教你基于Netty实现一个基础的RPC框架（通俗易懂）

在本篇文章中，我们继续围绕Netty手写实现RPC基础篇进行优化，主要引入几个点

• 集成spring，实现注解驱动配置
• 集成zookeeper，实现服务注册
• 增加负载均衡实现

源代码，加「跟着Mic学架构」微信号，回复『rpc』获取。

增加注解驱动

主要涉及到的修改模块

• netty-rpc-protocol
• netty-rpc-provider

netty-rpc-protocol

当前模块主要修改的类如下。

图7-1

下面针对netty-rpc-protocol模块的修改如下

增加注解驱动

这个注解的作用是用来指定某些服务为远程服务

@Target(ElementType.TYPE)// Target说明了Annotation所修饰的对象范围, TYPE:用于描述类、接口(包括注解类型) 或enum声明
@Retention(RetentionPolicy.RUNTIME)// Reteniton的作用是定义被它所注解的注解保留多久，保留至运行时。所以我们可以通过反射去获取注解信息。
@Component
public @interface GpRemoteService {

}

SpringRpcProviderBean

这个类主要用来在启动NettyServer，以及保存bean的映射关系

@Slf4j
public class SpringRpcProviderBean implements InitializingBean, BeanPostProcessor {

    private final int serverPort;
    private final String serverAddress;
    public SpringRpcProviderBean(int serverPort) throws UnknownHostException {
        this.serverPort = serverPort;
        InetAddress address=InetAddress.getLocalHost();
        this.serverAddress=address.getHostAddress();
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        log.info("begin deploy Netty Server to host {},on port {}",this.serverAddress,this.serverPort);
        new Thread(()->{
            try {
                new NettyServer(this.serverAddress,this.serverPort).startNettyServer();
            } catch (Exception e) {
                log.error("start Netty Server Occur Exception,",e);
                e.printStackTrace();
            }
        }).start();
    }

    //bean实例化后调用
    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        if(bean.getClass().isAnnotationPresent(GpRemoteService.class)){ //针对存在该注解的服务进行发布
            Method[] methods=bean.getClass().getDeclaredMethods();
            for(Method method: methods){ //保存需要发布的bean的映射
                String key=bean.getClass().getInterfaces()[0].getName()+"."+method.getName();
                BeanMethod beanMethod=new BeanMethod();
                beanMethod.setBean(bean);
                beanMethod.setMethod(method);
                Mediator.beanMethodMap.put(key,beanMethod);
            }
        }
        return bean;
    }
}

Mediator

主要管理bean以及调用

BeanMethod

@Data
public class BeanMethod {
    private Object bean;
    private Method method;
}

Mediator

负责持有发布bean的管理，以及bean的反射调用

public class Mediator {
    public static Map<String,BeanMethod> beanMethodMap=new ConcurrentHashMap<>();

    private volatile static Mediator instance=null;

    private Mediator(){
    }

    public static Mediator getInstance(){
        if(instance==null){
            synchronized (Mediator.class){
                if(instance==null){
                    instance=new Mediator();
                }
            }
        }
        return instance;
    }
    public Object processor(RpcRequest rpcRequest){
        String key=rpcRequest.getClassName()+"."+rpcRequest.getMethodName();
        BeanMethod beanMethod=beanMethodMap.get(key);
        if(beanMethod==null){
            return null;
        }
        Object bean=beanMethod.getBean();
        Method method=beanMethod.getMethod();
        try {
            return method.invoke(bean,rpcRequest.getParams());
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
        return null;
    }
}

RpcServerProperties

定义配置属性

@Data
@ConfigurationProperties(prefix = "gp.rpc")
public class RpcServerProperties {

    private int servicePort;
}

RpcProviderAutoConfiguration

定义自动配置类

@Configuration
@EnableConfigurationProperties(RpcServerProperties.class)
public class RpcProviderAutoConfiguration {

    @Bean
    public SpringRpcProviderBean rpcProviderBean(RpcServerProperties rpcServerProperties) throws UnknownHostException {
        return new SpringRpcProviderBean(rpcServerProperties.getServicePort());
    }
}

修改RpcServerHandler

修改调用方式，直接使用Mediator的调用即可。

public class RpcServerHandler extends SimpleChannelInboundHandler<RpcProtocol<RpcRequest>> {

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, RpcProtocol<RpcRequest> msg) throws Exception {
        RpcProtocol resProtocol=new RpcProtocol<>();
        Header header=msg.getHeader();
        header.setReqType(ReqType.RESPONSE.code());
        Object result=Mediator.getInstance().processor(msg.getContent()); //主要修改这个部分
        resProtocol.setHeader(header);
        RpcResponse response=new RpcResponse();
        response.setData(result);
        response.setMsg("success");
        resProtocol.setContent(response);

        ctx.writeAndFlush(resProtocol);
    }
}

netty-rpc-provider

这个模块中主要修改两个部分

• application.properties
• NettyRpcProviderMain

NettyRpcProviderMain

@ComponentScan(basePackages = {"com.example.spring.annotation","com.example.spring.service","com.example.service"})
@SpringBootApplication
public class NettyRpcProviderMain {

    public static void main(String[] args) throws Exception {
        SpringApplication.run(NettyRpcProviderMain.class, args);
        //去掉原来的实例化部分
    }
}

application.properties

增加一个配置属性。

gp.rpc.servicePort=20880

UserServiceImpl

把当前服务发布出去。

@GpRemoteService //表示将当前服务发布成远程服务
@Slf4j
public class UserServiceImpl implements IUserService {
    @Override
    public String saveUser(String name) {
        log.info("begin saveUser:"+name);
        return "Save User Success!";
    }
}

修改客户端的注解驱动

客户端同样也需要通过注解的方式来引用服务，这样就能够彻底的屏蔽掉远程通信的细节内容，代码结构如图7-2所示

图7-2

增加客户端注解

在netty-rpc-protocol模块的annotation目录下创建下面这个注解。

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
@Autowired
public @interface GpRemoteReference {
}

SpringRpcReferenceBean

定义工厂Bean，用来构建远程通信的代理

public class SpringRpcReferenceBean implements FactoryBean<Object> {

    private Class<?> interfaceClass;
    private Object object;
    private String serviceAddress;
    private int servicePort;

    @Override
    public Object getObject() throws Exception {
        return object;
    }

    public void init(){
        this.object= Proxy.newProxyInstance(this.interfaceClass.getClassLoader(),
                new Class<?>[]{this.interfaceClass},
                new RpcInvokerProxy(this.serviceAddress,this.servicePort));
    }

    @Override
    public Class<?> getObjectType() {
        return this.interfaceClass;
    }

    public void setInterfaceClass(Class<?> interfaceClass) {
        this.interfaceClass = interfaceClass;
    }

    public void setServiceAddress(String serviceAddress) {
        this.serviceAddress = serviceAddress;
    }

    public void setServicePort(int servicePort) {
        this.servicePort = servicePort;
    }
}

SpringRpcReferencePostProcessor

用来实现远程Bean的动态代理注入：

• BeanClassLoaderAware： 获取Bean的类装载器

• BeanFactoryPostProcessor：在spring容器加载了bean的定义文件之后，在bean实例化之前执行

• ApplicationContextAware： 获取上下文对象ApplicationContenxt

@Slf4j
public class SpringRpcReferencePostProcessor implements ApplicationContextAware, BeanClassLoaderAware, BeanFactoryPostProcessor {
    private ApplicationContext context;
    private ClassLoader classLoader;
    private RpcClientProperties clientProperties;

    public SpringRpcReferencePostProcessor(RpcClientProperties clientProperties) {
        this.clientProperties = clientProperties;
    }

    //保存发布的引用bean信息
    private final Map<String, BeanDefinition> rpcRefBeanDefinitions=new ConcurrentHashMap<>();

    @Override
    public void setBeanClassLoader(ClassLoader classLoader) {
        this.classLoader=classLoader;
    }
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.context=applicationContext;
    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        for (String beanDefinitionname:beanFactory.getBeanDefinitionNames()){
            //遍历bean定义，然后获取到加载的bean，遍历这些bean中的字段，是否携带GpRemoteReference注解
            //如果有，则需要构建一个动态代理实现
            BeanDefinition beanDefinition=beanFactory.getBeanDefinition(beanDefinitionname);
            String beanClassName=beanDefinition.getBeanClassName();
            if(beanClassName!=null){
                //和forName方法相同，内部就是直接调用的forName方法
                Class<?> clazz=ClassUtils.resolveClassName(beanClassName,this.classLoader);
                //针对当前类中的指定字段，动态创建一个Bean
                ReflectionUtils.doWithFields(clazz,this::parseRpcReference);
            }
        }
        //将@GpRemoteReference注解的bean，构建一个动态代理对象
        BeanDefinitionRegistry registry=(BeanDefinitionRegistry)beanFactory;
        this.rpcRefBeanDefinitions.forEach((beanName,beanDefinition)->{
            if(context.containsBean(beanName)){
                log.warn("SpringContext already register bean {}",beanName);
                return;
            }
            //把动态创建的bean注册到容器中
            registry.registerBeanDefinition(beanName,beanDefinition);
            log.info("registered RpcReferenceBean {} success.",beanName);
        });
    }
    private void parseRpcReference(Field field){
        GpRemoteReference gpRemoteReference=AnnotationUtils.getAnnotation(field,GpRemoteReference.class);
        if(gpRemoteReference!=null) {
            BeanDefinitionBuilder builder=BeanDefinitionBuilder.genericBeanDefinition(SpringRpcReferenceBean.class);
            builder.setInitMethodName(RpcConstant.INIT_METHOD_NAME);
            builder.addPropertyValue("interfaceClass",field.getType());
            builder.addPropertyValue("serviceAddress",clientProperties.getServiceAddress());
            builder.addPropertyValue("servicePort",clientProperties.getServicePort());
            BeanDefinition beanDefinition=builder.getBeanDefinition();
            rpcRefBeanDefinitions.put(field.getName(),beanDefinition);
        }
    }
}

需要在RpcConstant常量中增加一个INIT_METHOD_NAME属性

public class RpcConstant {
    //header部分的总字节数
    public final static int HEAD_TOTAL_LEN=16;
    //魔数
    public final static short MAGIC=0xca;

    public static final String INIT_METHOD_NAME = "init";
}

RpcClientProperties

@Data
public class RpcClientProperties {

    private String serviceAddress="192.168.1.102";

    private int servicePort=20880;
}

RpcRefernceAutoConfiguration

@Configuration
public class RpcRefernceAutoConfiguration implements EnvironmentAware{

    @Bean
    public SpringRpcReferencePostProcessor postProcessor(){
        String address=environment.getProperty("gp.serviceAddress");
        int port=Integer.parseInt(environment.getProperty("gp.servicePort"));
        RpcClientProperties rc=new RpcClientProperties();
        rc.setServiceAddress(address);
        rc.setServicePort(port);
        return new SpringRpcReferencePostProcessor(rc);
    }

    private Environment environment;

    @Override
    public void setEnvironment(Environment environment) {
        this.environment=environment;
    }
}

netty-rpc-consumer

修改netty-rpc-consumer模块

• 把该模块变成一个spring boot项目
• 增加web依赖
• 添加测试类

图7-3 netty-rpc-consumer模块

引入jar包依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

HelloController

@RestController
public class HelloController {

    @GpRemoteReference
    private IUserService userService;

    @GetMapping("/test")
    public String test(){
        return userService.saveUser("Mic");
    }
}

NettyConsumerMain

@ComponentScan(basePackages = {"com.example.spring.annotation","com.example.controller","com.example.spring.reference"})
@SpringBootApplication
public class NettyConsumerMain {
    public static void main(String[] args) {
        SpringApplication.run(NettyConsumerMain.class, args);
    }
}

application.properties

gp.serviceAddress=192.168.1.102
servicePort.servicePort=20880

访问测试

• 启动Netty-Rpc-Server
• 启动Netty-Rpc-Consumer

如果启动过程没有任何问题，则可以访问HelloController来测试远程服务的访问。

引入注册中心

创建一个netty-rpc-registry模块，代码结构如图7-4所示。

引入相关依赖

<dependency>
    <groupId>org.apache.curator</groupId>
    <artifactId>curator-framework</artifactId>
    <version>4.2.0</version>
</dependency>
<dependency>
    <groupId>org.apache.curator</groupId>
    <artifactId>curator-recipes</artifactId>
    <version>4.2.0</version>
</dependency>
<dependency>
    <groupId>org.apache.curator</groupId>
    <artifactId>curator-x-discovery</artifactId>
    <version>4.2.0</version>
</dependency>

IRegistryService

public interface IRegistryService {

    /**
     * 注册服务
     * @param serviceInfo
     * @throws Exception
     */
    void register(ServiceInfo serviceInfo) throws Exception;

    /**
     * 取消注册
     * @param serviceInfo
     * @throws Exception
     */
    void unRegister(ServiceInfo serviceInfo) throws Exception;

    /**
     * 动态发现服务
     * @param serviceName
     * @return
     * @throws Exception
     */
    ServiceInfo discovery(String serviceName) throws Exception;
}

ServiceInfo

@Data
public class ServiceInfo {
    private String serviceName;
    private String serviceAddress;
    private int servicePort;
}

ZookeeperRegistryService

@Slf4j
public class ZookeeperRegistryService implements IRegistryService {

    private static final String REGISTRY_PATH="/registry";
    //Curator中提供的服务注册与发现的组件封装，它对此抽象出了ServiceInstance、
    // ServiceProvider、ServiceDiscovery三个接口，通过它我们可以很轻易的实现Service Discovery
    private final ServiceDiscovery<ServiceInfo> serviceDiscovery;

    private ILoadBalance<ServiceInstance<ServiceInfo>> loadBalance;

    public ZookeeperRegistryService(String registryAddress) throws Exception {
        CuratorFramework client= CuratorFrameworkFactory
                .newClient(registryAddress,new ExponentialBackoffRetry(1000,3));
        JsonInstanceSerializer<ServiceInfo> serializer=new JsonInstanceSerializer<>(ServiceInfo.class);
        this.serviceDiscovery= ServiceDiscoveryBuilder.builder(ServiceInfo.class)
                .client(client)
                .serializer(serializer)
                .basePath(REGISTRY_PATH)
                .build();
        this.serviceDiscovery.start();
        loadBalance=new RandomLoadBalance();
    }

    @Override
    public void register(ServiceInfo serviceInfo) throws Exception {
        log.info("开始注册服务，{}",serviceInfo);
        ServiceInstance<ServiceInfo> serviceInstance=ServiceInstance
                .<ServiceInfo>builder().name(serviceInfo.getServiceName())
                .address(serviceInfo.getServiceAddress())
                .port(serviceInfo.getServicePort())
                .payload(serviceInfo)
                .build();
        serviceDiscovery.registerService(serviceInstance);
    }

    @Override
    public void unRegister(ServiceInfo serviceInfo) throws Exception {
        ServiceInstance<ServiceInfo> serviceInstance=ServiceInstance.<ServiceInfo>builder()
                .name(serviceInfo.getServiceName())
                .address(serviceInfo.getServiceAddress())
                .port(serviceInfo.getServicePort())
                .payload(serviceInfo)
                .build();
        serviceDiscovery.unregisterService(serviceInstance);
    }

    @Override
    public ServiceInfo discovery(String serviceName) throws Exception {
        Collection<ServiceInstance<ServiceInfo>> serviceInstances= serviceDiscovery
                .queryForInstances(serviceName);
        //通过负载均衡返回某个具体实例
        ServiceInstance<ServiceInfo> serviceInstance=loadBalance.select((List<ServiceInstance<ServiceInfo>>)serviceInstances);
        if(serviceInstance!=null){
            return serviceInstance.getPayload();
        }
        return null;
    }
}

引入负载均衡算法

由于服务端发现服务时可能有多个，所以需要用到负载均衡算法来实现

ILoadBalance

public interface ILoadBalance<T> {

    T select(List<T> servers);
}

AbstractLoadBalance

public abstract class AbstractLoadBanalce implements ILoadBalance<ServiceInstance<ServiceInfo>> {

    @Override
    public ServiceInstance<ServiceInfo> select(List<ServiceInstance<ServiceInfo>> servers){
        if(servers==null||servers.size()==0){
            return null;
        }
        if(servers.size()==1){
            return servers.get(0);
        }
        return doSelect(servers);
    }

    protected abstract ServiceInstance<ServiceInfo> doSelect(List<ServiceInstance<ServiceInfo>> servers);
}

RandomLoadBalance

public class RandomLoadBalance extends AbstractLoadBanalce {
    @Override
    protected ServiceInstance<ServiceInfo> doSelect(List<ServiceInstance<ServiceInfo>> servers) {
        int length=servers.size();
        Random random=new Random();
        return servers.get(random.nextInt(length));
    }
}

RegistryType

public enum RegistryType {

    ZOOKEEPER((byte)0),
    EUREKA((byte)1);

    private byte code;

    RegistryType(byte code) {
        this.code=code;
    }

    public byte code(){
        return this.code;
    }

    public static RegistryType findByCode(byte code) {
        for (RegistryType rt : RegistryType.values()) {
            if (rt.code() == code) {
                return rt;
            }
        }
        return null;
    }
}

RegistryFactory

public class RegistryFactory {

    public static IRegistryService createRegistryService(String address,RegistryType registryType){
        IRegistryService registryService=null;
        try {
            switch (registryType) {
                case ZOOKEEPER:
                    registryService = new ZookeeperRegistryService(address);
                    break;
                case EUREKA:
                    //TODO
                    break;
                default:
                    registryService = new ZookeeperRegistryService(address);
                    break;
            }
        }catch (Exception e){
            e.printStackTrace();
        }
        return registryService;
    }
}

修改服务端增加服务注册

修改netty-rpc-protocol模块，加入注册中心的支持

SpringRpcProviderBean

按照下面case标注部分，表示要修改的内容

@Slf4j
public class SpringRpcProviderBean implements InitializingBean, BeanPostProcessor {

    private final int serverPort;
    private final String serverAddress;
    private final IRegistryService registryService; //修改部分,增加注册中心实现
    public SpringRpcProviderBean(int serverPort,IRegistryService registryService) throws UnknownHostException {
        this.serverPort = serverPort;
        InetAddress address=InetAddress.getLocalHost();
        this.serverAddress=address.getHostAddress();
        this.registryService=registryService; //修改部分,增加注册中心实现
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        log.info("begin deploy Netty Server to host {},on port {}",this.serverAddress,this.serverPort);
        new Thread(()->{
            try {
                new NettyServer(this.serverAddress,this.serverPort).startNettyServer();
            } catch (Exception e) {
                log.error("start Netty Server Occur Exception,",e);
                e.printStackTrace();
            }
        }).start();
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        if(bean.getClass().isAnnotationPresent(GpRemoteService.class)){ //针对存在该注解的服务进行发布
            Method[] methods=bean.getClass().getDeclaredMethods();
            for(Method method: methods){
                String serviceName=bean.getClass().getInterfaces()[0].getName();
                String key=serviceName+"."+method.getName();
                BeanMethod beanMethod=new BeanMethod();
                beanMethod.setBean(bean);
                beanMethod.setMethod(method);
                Mediator.beanMethodMap.put(key,beanMethod);
                try {
                    //修改部分,增加注册中心实现
                    ServiceInfo serviceInfo = new ServiceInfo();
                    serviceInfo.setServiceAddress(this.serverAddress);
                    serviceInfo.setServicePort(this.serverPort);
                    serviceInfo.setServiceName(serviceName);
                    registryService.register(serviceInfo);//修改部分,增加注册中心实现
                }catch (Exception e){
                    log.error("register service {} faild",serviceName,e);
                }
            }
        }
        return bean;
    }
}

RpcServerProperties

修改RpcServerProperties，增加注册中心的配置

@Data
@ConfigurationProperties(prefix = "gp.rpc")
public class RpcServerProperties {

    private int servicePort;

    private byte registerType;

    private String registryAddress;
}

RpcProviderAutoConfiguration

增加注册中心的注入。

@Configuration
@EnableConfigurationProperties(RpcServerProperties.class)
public class RpcProviderAutoConfiguration {

    @Bean
    public SpringRpcProviderBean rpcProviderBean(RpcServerProperties rpcServerProperties) throws UnknownHostException {
        //添加注册中心
        IRegistryService registryService=RegistryFactory.createRegistryService(rpcServerProperties.getRegistryAddress(), RegistryType.findByCode(rpcServerProperties.getRegisterType()));
        return new SpringRpcProviderBean(rpcServerProperties.getServicePort(),registryService);
    }
}

application.properties

修改netty-rpc-provider中的application.properties。

gp.rpc.servicePort=20880
gp.rpc.registerType=0
gp.rpc.registryAddress=192.168.221.128:2181

修改客户端，增加服务发现

客户端需要修改的地方较多，下面这些修改的代码，都是netty-rpc-protocol模块中的类。

RpcClientProperties

增加注册中心类型和注册中心地址的选项

@Data
public class RpcClientProperties {

    private String serviceAddress="192.168.1.102";

    private int servicePort=20880;

    private byte registryType;

    private String registryAddress;

}

修改NettyClient

原本是静态地址，现在修改成了从注册中心获取地址

@Slf4j
public class NettyClient {
    private final Bootstrap bootstrap;
    private final EventLoopGroup eventLoopGroup=new NioEventLoopGroup();
   /* private String serviceAddress;
    private int servicePort;*/
    public NettyClient(){
        log.info("begin init NettyClient");
        bootstrap=new Bootstrap();
        bootstrap.group(eventLoopGroup)
                .channel(NioSocketChannel.class)
                .handler(new RpcClientInitializer());
       /* this.serviceAddress=serviceAddress;
        this.servicePort=servicePort;*/
    }

    public void sendRequest(RpcProtocol<RpcRequest> protocol, IRegistryService registryService) throws Exception {
        ServiceInfo serviceInfo=registryService.discovery(protocol.getContent().getClassName());
        ChannelFuture future=bootstrap.connect(serviceInfo.getServiceAddress(),serviceInfo.getServicePort()).sync();
        future.addListener(listener->{
            if(future.isSuccess()){
                log.info("connect rpc server {} success.",serviceInfo.getServiceAddress());
            }else{
                log.error("connect rpc server {} failed .",serviceInfo.getServiceAddress());
                future.cause().printStackTrace();
                eventLoopGroup.shutdownGracefully();
            }
        });
        log.info("begin transfer data");
        future.channel().writeAndFlush(protocol);
    }
}

修改RpcInvokerProxy

将静态ip和地址，修改成IRegistryService

@Slf4j
public class RpcInvokerProxy implements InvocationHandler {

   /* private String serviceAddress;
    private int servicePort;*/

    IRegistryService registryService;

    public RpcInvokerProxy(IRegistryService registryService) {
       /* this.serviceAddress = serviceAddress;
        this.servicePort = servicePort;*/
        this.registryService=registryService;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        log.info("begin invoke target server");
        //组装参数
        RpcProtocol<RpcRequest> protocol=new RpcProtocol<>();
        long requestId= RequestHolder.REQUEST_ID.incrementAndGet();
        Header header=new Header(RpcConstant.MAGIC, SerialType.JSON_SERIAL.code(), ReqType.REQUEST.code(),requestId,0);
        protocol.setHeader(header);
        RpcRequest request=new RpcRequest();
        request.setClassName(method.getDeclaringClass().getName());
        request.setMethodName(method.getName());
        request.setParameterTypes(method.getParameterTypes());
        request.setParams(args);
        protocol.setContent(request);
        //发送请求
        NettyClient nettyClient=new NettyClient();
        //构建异步数据处理
        RpcFuture<RpcResponse> future=new RpcFuture<>(new DefaultPromise<>(new DefaultEventLoop()));
        RequestHolder.REQUEST_MAP.put(requestId,future);
        nettyClient.sendRequest(protocol,this.registryService);
        return future.getPromise().get().getData();
    }
}

SpringRpcReferenceBean

修改引用bean，增加注册中心配置

public class SpringRpcReferenceBean implements FactoryBean<Object> {

    private Class<?> interfaceClass;
    private Object object;
   /* private String serviceAddress;
    private int servicePort;*/
    //修改增加注册中心
    private byte registryType;
    private String registryAddress;

    @Override
    public Object getObject() throws Exception {
        return object;
    }

    public void init(){
        //修改增加注册中心
        IRegistryService registryService= RegistryFactory.createRegistryService(this.registryAddress, RegistryType.findByCode(this.registryType));
        this.object= Proxy.newProxyInstance(this.interfaceClass.getClassLoader(),
                new Class<?>[]{this.interfaceClass},
                new RpcInvokerProxy(registryService));
    }

    @Override
    public Class<?> getObjectType() {
        return this.interfaceClass;
    }

    public void setInterfaceClass(Class<?> interfaceClass) {
        this.interfaceClass = interfaceClass;
    }

   /* public void setServiceAddress(String serviceAddress) {
        this.serviceAddress = serviceAddress;
    }

    public void setServicePort(int servicePort) {
        this.servicePort = servicePort;
    }*/

    public void setRegistryType(byte registryType) {
        this.registryType = registryType;
    }

    public void setRegistryAddress(String registryAddress) {
        this.registryAddress = registryAddress;
    }
}

SpringRpcReferencePostProcessor

@Slf4j
public class SpringRpcReferencePostProcessor implements ApplicationContextAware, BeanClassLoaderAware, BeanFactoryPostProcessor {
    private ApplicationContext context;
    private ClassLoader classLoader;
    private RpcClientProperties clientProperties;

    public SpringRpcReferencePostProcessor(RpcClientProperties clientProperties) {
        this.clientProperties = clientProperties;
    }

    //保存发布的引用bean信息
    private final Map<String, BeanDefinition> rpcRefBeanDefinitions=new ConcurrentHashMap<>();

    @Override
    public void setBeanClassLoader(ClassLoader classLoader) {
        this.classLoader=classLoader;
    }
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.context=applicationContext;
    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        for (String beanDefinitionname:beanFactory.getBeanDefinitionNames()){
            //遍历bean定义，然后获取到加载的bean，遍历这些bean中的字段，是否携带GpRemoteReference注解
            //如果有，则需要构建一个动态代理实现
            BeanDefinition beanDefinition=beanFactory.getBeanDefinition(beanDefinitionname);
            String beanClassName=beanDefinition.getBeanClassName();
            if(beanClassName!=null){
                Class<?> clazz=ClassUtils.resolveClassName(beanClassName,this.classLoader);
                ReflectionUtils.doWithFields(clazz,this::parseRpcReference);
            }
        }
        //将@GpRemoteReference注解的bean，构建一个动态代理对象
        BeanDefinitionRegistry registry=(BeanDefinitionRegistry)beanFactory;
        this.rpcRefBeanDefinitions.forEach((beanName,beanDefinition)->{
            if(context.containsBean(beanName)){
                log.warn("SpringContext already register bean {}",beanName);
                return;
            }
            registry.registerBeanDefinition(beanName,beanDefinition);
            log.info("registered RpcReferenceBean {} success.",beanName);
        });
    }
    private void parseRpcReference(Field field){
        GpRemoteReference gpRemoteReference=AnnotationUtils.getAnnotation(field,GpRemoteReference.class);
        if(gpRemoteReference!=null) {
            BeanDefinitionBuilder builder=BeanDefinitionBuilder.genericBeanDefinition(SpringRpcReferenceBean.class);
            builder.setInitMethodName(RpcConstant.INIT_METHOD_NAME);
            builder.addPropertyValue("interfaceClass",field.getType());
            /*builder.addPropertyValue("serviceAddress",clientProperties.getServiceAddress());
            builder.addPropertyValue("servicePort",clientProperties.getServicePort());*/
            builder.addPropertyValue("registryType",clientProperties.getRegistryType());
            builder.addPropertyValue("registryAddress",clientProperties.getRegistryAddress());
            BeanDefinition beanDefinition=builder.getBeanDefinition();
            rpcRefBeanDefinitions.put(field.getName(),beanDefinition);
        }
    }
}

RpcRefernceAutoConfiguration

@Configuration
public class RpcRefernceAutoConfiguration implements EnvironmentAware{

    @Bean
    public SpringRpcReferencePostProcessor postProcessor(){
        String address=environment.getProperty("gp.serviceAddress");
        int port=Integer.parseInt(environment.getProperty("gp.servicePort"));
        RpcClientProperties rc=new RpcClientProperties();
        rc.setServiceAddress(address);
        rc.setServicePort(port);
        rc.setRegistryType(Byte.parseByte(environment.getProperty("gp.registryType")));
        rc.setRegistryAddress(environment.getProperty("gp.registryAddress"));
        return new SpringRpcReferencePostProcessor(rc);
    }

    private Environment environment;

    @Override
    public void setEnvironment(Environment environment) {
        this.environment=environment;
    }
}

application.properties

修改netty-rpc-consumer模块中的配置

gp.serviceAddress=192.168.1.102
gp.servicePort=20880

gp.registryType=0
gp.registryAddress=192.168.221.128:2181

负载均衡的测试

增加一个服务端的启动类，并且修改端口。然后客户端不需要重启的情况下刷新浏览器，即可看到负载均衡的效果。

图7-5

需要源码的同学，请关注公众号[跟着Mic学架构]，回复关键字[rpc]，即可获得

版权声明：本博客所有文章除特别声明外，均采用 CC BY-NC-SA 4.0 许可协议。转载请注明来自 Mic带你学架构！

如果本篇文章对您有帮助，还请帮忙点个关注和赞，您的坚持是我不断创作的动力。欢迎关注「跟着Mic学架构」公众号公众号获取更多技术干货！