自己动手从0开始实现一个分布式RPC框架

+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ |  BYTE  |        |        |        |        |        |        |             ........ +--------------------------------------------+--------+-----------------+--------+--------+--------+--------+--------+--------+-----------------+ |  magic | version|  type  |           content lenth           |                   content byte[]                                        |        | +--------+-----------------------------------------------------------------------------------------+--------------------------------------------+

    @Override    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)        throws BeansException {        this.beanFactory = beanFactory;        postProcessRpcConsumerBeanFactory(beanFactory, (BeanDefinitionRegistry)beanFactory);    }
    private void postProcessRpcConsumerBeanFactory(ConfigurableListableBeanFactory beanFactory, BeanDefinitionRegistry beanDefinitionRegistry) {        String[] beanDefinitionNames = beanFactory.getBeanDefinitionNames();        int len = beanDefinitionNames.length;        for (int i = 0; i < len; i++) {            String beanDefinitionName = beanDefinitionNames[i];            BeanDefinition beanDefinition = beanFactory.getBeanDefinition(beanDefinitionName);            String beanClassName = beanDefinition.getBeanClassName();            if (beanClassName != null) {                Class<?> clazz = ClassUtils.resolveClassName(beanClassName, classLoader);                ReflectionUtils.doWithFields(clazz, new FieldCallback() {                    @Override                    public void doWith(Field field) throws IllegalArgumentException, IllegalAccessException {                        parseField(field);                    }                });            }
        }
        Iterator<Entry<String, BeanDefinition>> it = beanDefinitions.entrySet().iterator();        while (it.hasNext()) {            Entry<String, BeanDefinition> entry = it.next();            if (context.containsBean(entry.getKey())) {                throw new IllegalArgumentException("Spring context already has a bean named " + entry.getKey());            }            beanDefinitionRegistry.registerBeanDefinition(entry.getKey(), entry.getValue());            log.info("register OrcRpcConsumerBean definition: {}", entry.getKey());        }
    }
    private void parseField(Field field) {        // 获取所有OrcRpcConsumer注解        OrcRpcConsumer orcRpcConsumer = field.getAnnotation(OrcRpcConsumer.class);        if (orcRpcConsumer != null) {            // 使用field的类型和OrcRpcConsumer注解一起生成BeanDefinition            OrcRpcConsumerBeanDefinitionBuilder beanDefinitionBuilder = new OrcRpcConsumerBeanDefinitionBuilder(field.getType(), orcRpcConsumer);            BeanDefinition beanDefinition = beanDefinitionBuilder.build();            beanDefinitions.put(field.getName(), beanDefinition);        }    }

public class JdkProxyFactory implements ProxyFactory{
    @Override    public Object getProxy(ServiceMetadata serviceMetadata) {        return Proxy            .newProxyInstance(serviceMetadata.getClazz().getClassLoader(), new Class[] {serviceMetadata.getClazz()},                new ClientInvocationHandler(serviceMetadata));    }
    private class ClientInvocationHandler implements InvocationHandler {
        private ServiceMetadata serviceMetadata;
        public ClientInvocationHandler(ServiceMetadata serviceMetadata) {            this.serviceMetadata = serviceMetadata;        }
        @Override        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {            String serviceId = ServiceUtils.getServiceId(serviceMetadata);            // 通过负载均衡器选取一个服务提供方地址            ServiceURL service = InvocationServiceSelector.select(serviceMetadata);
            OrcRpcRequest request = new OrcRpcRequest();            request.setMethod(method.getName());            request.setParameterTypes(method.getParameterTypes());            request.setParameters(args);            request.setRequestId(UUID.randomUUID().toString());            request.setServiceId(serviceId);
            OrcRpcResponse response = InvocationClientContainer.getInvocationClient(service.getServerNet()).invoke(request, service);            if (response.getStatus() == RpcStatusEnum.SUCCESS) {                return response.getData();            } else if (response.getException() != null) {                throw new OrcRpcException(response.getException().getMessage());            } else {                throw new OrcRpcException(response.getStatus().name());            }        }    }}

+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+--------+ |  BYTE  |        |        |        |        |        |        |             ........ +--------------------------------------------+--------+-----------------+--------+--------+--------+--------+--------+--------+-----------------+ |  magic | version|  type  |           content lenth           |                   content byte[]                                        |        | +--------+-----------------------------------------------------------------------------------------+--------------------------------------------+

@Overrideprotected void encode(ChannelHandlerContext channelHandlerContext, ProtocolMsg protocolMsg, ByteBuf byteBuf)    throws Exception {    // 写入协议头    byteBuf.writeByte(ProtocolConstant.MAGIC);    // 写入版本    byteBuf.writeByte(ProtocolConstant.DEFAULT_VERSION);    // 写入请求类型    byteBuf.writeByte(protocolMsg.getMsgType());    // 写入消息长度    byteBuf.writeInt(protocolMsg.getContent().length);    // 写入消息内容    byteBuf.writeBytes(protocolMsg.getContent());}

/** * 协议开始的标志 magic + version + type + length 占据7个字节 */public final int BASE_LENGTH = 7;
@Overrideprotected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, List<Object> list)    throws Exception {    // 可读字节小于基本长度，无法解析出payload长度，返回    if (byteBuf.readableBytes() < BASE_LENGTH) {        return;    }    // 记录包头开始的index    int beginIndex;    while (true) {        // 记录包头开始的index        beginIndex = byteBuf.readerIndex();        // 标记包头开始的index        byteBuf.markReaderIndex();        // 读到了协议头魔数，结束循环        if (byteBuf.readByte() == ProtocolConstant.MAGIC) {            break;        }        // 未读到包头，略过一个字节        // 每次略过一个字节，去读取包头信息的开始标记        byteBuf.resetReaderIndex();        byteBuf.readByte();
        /**         * 当略过，一个字节之后，数据包的长度，又变得不满足         * 此时结束。等待后面的数据到达         */        if (byteBuf.readableBytes() < BASE_LENGTH) {            return;        }    }    // 读取版本号    byte version = byteBuf.readByte();    // 读取消息类型    byte type = byteBuf.readByte();    // 读取消息长度    int length = byteBuf.readInt();    // 判断本包是否完整    if (byteBuf.readableBytes() < length) {        // 还原读指针        byteBuf.readerIndex(beginIndex);        return;    }    byte[] data = new byte[length];    byteBuf.readBytes(data);
    ProtocolMsg msg = new ProtocolMsg();    msg.setMsgType(type);    msg.setContent(data);    list.add(msg);}