javaweb dubbo源码解析（一）ServiceConfig

dubbo源码解析（一）ServiceConfig

Open www1350 opened this issue 6 years ago • 0 comments

什么是Dubbo?

Dubbo是阿里巴巴公司开源的一个高性能优秀的服务框架，使得应用可通过高性能的RPC实现服务的输出和输入功能，以及SOA服务治理方案，和spring框架无缝集成。

dubbo作为一个非常好的rpc项目，广泛在国内使用。

官网：http://dubbo.incubator.apache.org/

github地址：https://github.com/apache/incubator-dubbo

我们先看下项目结构：

模块说明：

dubbo-common 公共逻辑模块：包括 Util 类和通用模型。
dubbo-remoting 远程通讯模块：相当于 Dubbo 协议的实现，如果 RPC 用 RMI协议则不需要使用此包。
dubbo-rpc 远程调用模块：抽象各种协议，以及动态代理，只包含一对一的调用，不关心集群的管理。
dubbo-cluster 集群模块：将多个服务提供方伪装为一个提供方，包括：负载均衡, 容错，路由等，集群的地址列表可以是静态配置的，也可以是由注册中心下发。
dubbo-registry 注册中心模块：基于注册中心下发地址的集群方式，以及对各种注册中心的抽象。
dubbo-monitor 监控模块：统计服务调用次数，调用时间的，调用链跟踪的服务。
dubbo-config 配置模块：是 Dubbo 对外的 API，用户通过 Config 使用D ubbo，隐藏 Dubbo 所有细节。
dubbo-container 容器模块：是一个 Standlone 的容器，以简单的 Main 加载 Spring 启动，因为服务通常不需要 Tomcat/JBoss 等 Web 容器的特性，没必要用 Web 容器去加载服务。

整体上按照分层结构进行分包，与分层的不同点在于：

container 为服务容器，用于部署运行服务，没有在层中画出。
protocol 层和 proxy 层都放在 rpc 模块中，这两层是 rpc 的核心，在不需要集群也就是只有一个提供者时，可以只使用这两层完成 rpc 调用。
transport 层和 exchange 层都放在 remoting 模块中，为 rpc 调用的通讯基础。
serialize 层放在 common 模块中，以便更大程度复用。

dubbo-framework

图例说明：

图中左边淡蓝背景的为服务消费方使用的接口，右边淡绿色背景的为服务提供方使用的接口，位于中轴线上的为双方都用到的接口。
图中从下至上分为十层，各层均为单向依赖，右边的黑色箭头代表层之间的依赖关系，每一层都可以剥离上层被复用，其中，Service 和 Config 层为 API，其它各层均为 SPI。
图中绿色小块的为扩展接口，蓝色小块为实现类，图中只显示用于关联各层的实现类。
图中蓝色虚线为初始化过程，即启动时组装链，红色实线为方法调用过程，即运行时调时链，紫色三角箭头为继承，可以把子类看作父类的同一个节点，线上的文字为调用的方法。

各层说明

config 配置层：对外配置接口，以 ServiceConfig, ReferenceConfig 为中心，可以直接初始化配置类，也可以通过 spring 解析配置生成配置类
proxy 服务代理层：服务接口透明代理，生成服务的客户端 Stub 和服务器端 Skeleton, 以 ServiceProxy 为中心，扩展接口为 ProxyFactory
registry 注册中心层：封装服务地址的注册与发现，以服务 URL 为中心，扩展接口为 RegistryFactory, Registry, RegistryService
cluster 路由层：封装多个提供者的路由及负载均衡，并桥接注册中心，以 Invoker 为中心，扩展接口为 Cluster, Directory, Router, LoadBalance
monitor 监控层：RPC 调用次数和调用时间监控，以 Statistics 为中心，扩展接口为 MonitorFactory, Monitor, MonitorService
protocol 远程调用层：封装 RPC 调用，以 Invocation, Result 为中心，扩展接口为 Protocol, Invoker, Exporter
exchange 信息交换层：封装请求响应模式，同步转异步，以 Request, Response 为中心，扩展接口为 Exchanger, ExchangeChannel, ExchangeClient, ExchangeServer
transport 网络传输层：抽象 mina 和 netty 为统一接口，以 Message 为中心，扩展接口为 Channel, Transporter, Client, Server, Codec
serialize 数据序列化层：可复用的一些工具，扩展接口为 Serialization, ObjectInput, ObjectOutput, ThreadPool

启动demo

dubbo-demo里面有一个例子，一个消费者一个提供者

dubbo-demo-api

public interface DemoService {

    String sayHello(String name);

}

dubbo-demo-provider

public class DemoServiceImpl implements DemoService {

    public String sayHello(String name) {
        System.out.println("[" + new SimpleDateFormat("HH:mm:ss").format(new Date()) + "] Hello " + name + ", request from consumer: " + RpcContext.getContext().getRemoteAddress());
        return "Hello " + name + ", response from provider: " + RpcContext.getContext().getLocalAddress();
    }

}

public class Provider {

    public static void main(String[] args) throws Exception {
        //Prevent to get IPV6 address,this way only work in debug mode
        //But you can pass use -Djava.net.preferIPv4Stack=true,then it work well whether in debug mode or not
        System.setProperty("java.net.preferIPv4Stack", "true");
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[]{"META-INF/spring/dubbo-demo-provider.xml"});
        context.start();

        System.in.read(); // press any key to exit
    }

}

dubbo-demo-provider.xml

<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
       xmlns="http://www.springframework.org/schema/beans"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
       http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">

    <!-- provider's application name, used for tracing dependency relationship -->
    <dubbo:application name="demo-provider"/>

    <!-- use multicast registry center to export service -->
    <dubbo:registry address="zookeeper://localhost:2181"/>

    <!-- use dubbo protocol to export service on port 20880 -->
    <dubbo:protocol name="dubbo" port="20880"/>

    <!-- service implementation, as same as regular local bean -->
    <bean id="demoService" class="com.alibaba.dubbo.demo.provider.DemoServiceImpl"/>

    <!-- declare the service interface to be exported -->
    <dubbo:service interface="com.alibaba.dubbo.demo.DemoService" ref="demoService"/>

</beans>

dubbo-demo-consumer

public class Consumer {

    public static void main(String[] args) {
        //Prevent to get IPV6 address,this way only work in debug mode
        //But you can pass use -Djava.net.preferIPv4Stack=true,then it work well whether in debug mode or not
        System.setProperty("java.net.preferIPv4Stack", "true");
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[]{"META-INF/spring/dubbo-demo-consumer.xml"});
        context.start();
        DemoService demoService = (DemoService) context.getBean("demoService"); // get remote service proxy
        while (true) {
            try {
                Thread.sleep(1000);
                String hello = demoService.sayHello("world"); // call remote method
                System.out.println(hello); // get result
            } catch (Throwable throwable) {
                throwable.printStackTrace();
            }
        }

    }
}

dubbo-demo-consumer.xml

<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
       xmlns="http://www.springframework.org/schema/beans"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
       http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">

    <!-- consumer's application name, used for tracing dependency relationship (not a matching criterion),
    don't set it same as provider -->
    <dubbo:application name="demo-consumer"/>

    <!-- use multicast registry center to discover service -->
    <dubbo:registry address="zookeeper://localhost:2181"/>

    <!-- generate proxy for the remote service, then demoService can be used in the same way as the
    local regular interface -->
    <dubbo:reference id="demoService" check="false" interface="com.alibaba.dubbo.demo.DemoService"/>

</beans>

启动provider后

我们可以看到zk里面的状况

会出现两个节点/dubbo/com.alibaba.dubbo.demo.DemoService/configurators和/dubbo/com.alibaba.dubbo.demo.DemoService/providers

我们对他解码可以看到

dubbo://172.17.8.254:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&dubbo=2.0.0&generic=false&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=85385&side=provider&timestamp=1522303604681

启动consumer后

zk的节点/dubbo/com.alibaba.dubbo.demo.DemoService下多了routers, consumers两个节点

consumers再次解码可以看到

consumer://172.17.8.254/com.alibaba.dubbo.demo.DemoService?application=demo-consumer&category=consumers&check=false&dubbo=2.0.0&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=85452&qos.port=33333&side=consumer&timestamp=1522303933804

最后我们看到控制台每秒打印

xml解析分析

public class DubboNamespaceHandler extends NamespaceHandlerSupport {
    static {
        Version.checkDuplicate(DubboNamespaceHandler.class);
    }

    public void init() {
        //分别解析到对应的config类
        registerBeanDefinitionParser("application", new DubboBeanDefinitionParser(ApplicationConfig.class, true));
        registerBeanDefinitionParser("module", new DubboBeanDefinitionParser(ModuleConfig.class, true));
        registerBeanDefinitionParser("registry", new DubboBeanDefinitionParser(RegistryConfig.class, true));
        registerBeanDefinitionParser("monitor", new DubboBeanDefinitionParser(MonitorConfig.class, true));
        registerBeanDefinitionParser("provider", new DubboBeanDefinitionParser(ProviderConfig.class, true));
        registerBeanDefinitionParser("consumer", new DubboBeanDefinitionParser(ConsumerConfig.class, true));
        registerBeanDefinitionParser("protocol", new DubboBeanDefinitionParser(ProtocolConfig.class, true));
        registerBeanDefinitionParser("service", new DubboBeanDefinitionParser(ServiceBean.class, true));
        registerBeanDefinitionParser("reference", new DubboBeanDefinitionParser(ReferenceBean.class, false));
        registerBeanDefinitionParser("annotation", new AnnotationBeanDefinitionParser());
    }
}

DubboBeanDefinitionParser里面包含了解析xml的行为，就不具体展开

config 配置层

ServiceBean源码分析

ApplicationContextAware

public void setApplicationContext(ApplicationContext applicationContext) {
    this.applicationContext = applicationContext;
    //加入SpringExtensionFactory
    SpringExtensionFactory.addApplicationContext(applicationContext);
    if (applicationContext != null) {
        SPRING_CONTEXT = applicationContext;
        try {
            //反射AbstractApplicationContext的addApplicationListener将本类实例加入，监听容器加载完成后调用onApplicationEvent方法
            Method method = applicationContext.getClass().getMethod("addApplicationListener", new Class<?>[]{ApplicationListener.class}); // backward compatibility to spring 2.0.1
            method.invoke(applicationContext, new Object[]{this});
            supportedApplicationListener = true;
        } catch (Throwable t) {
            if (applicationContext instanceof AbstractApplicationContext) {
                try {
                    Method method = AbstractApplicationContext.class.getDeclaredMethod("addListener", new Class<?>[]{ApplicationListener.class}); // backward compatibility to spring 2.0.1
                    if (!method.isAccessible()) {
                        method.setAccessible(true);
                    }
                    method.invoke(applicationContext, new Object[]{this});
                    supportedApplicationListener = true;
                } catch (Throwable t2) {
                }
            }
        }
    }
}

继承ApplicationListener<ContextRefreshedEvent> 监听事件，bean加载的最后调用

public void onApplicationEvent(ContextRefreshedEvent event) {
    //delay是-1或者没配置就延迟到Spring 初始化完成后，再暴露服务
    if (isDelay() && !isExported() && !isUnexported()) {
        if (logger.isInfoEnabled()) {
            logger.info("The service ready on spring started. service: " + getInterface());
        }
        export();
    }
}

bean被初始化的时候利用InitializingBean

public void afterPropertiesSet() throws Exception {
    if (getProvider() == null) {
        Map<String, ProviderConfig> providerConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProviderConfig.class, false, false);
        if (providerConfigMap != null && providerConfigMap.size() > 0) {
            Map<String, ProtocolConfig> protocolConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProtocolConfig.class, false, false);
            if ((protocolConfigMap == null || protocolConfigMap.size() == 0)
                    && providerConfigMap.size() > 1) { // backward compatibility
                List<ProviderConfig> providerConfigs = new ArrayList<ProviderConfig>();
                for (ProviderConfig config : providerConfigMap.values()) {
                    if (config.isDefault() != null && config.isDefault().booleanValue()) {
                        providerConfigs.add(config);
                    }
                }
                if (!providerConfigs.isEmpty()) {
                    setProviders(providerConfigs);
                }
            } else {
                ProviderConfig providerConfig = null;
                for (ProviderConfig config : providerConfigMap.values()) {
                    if (config.isDefault() == null || config.isDefault().booleanValue()) {
                        if (providerConfig != null) {
                            throw new IllegalStateException("Duplicate provider configs: " + providerConfig + " and " + config);
                        }
                        providerConfig = config;
                    }
                }
                if (providerConfig != null) {
                    setProvider(providerConfig);
                }
            }
        }
    }
    if (getApplication() == null
            && (getProvider() == null || getProvider().getApplication() == null)) {
        //"demo-provider" -> "<dubbo:application name="demo-provider" id="demo-provider" />"
        Map<String, ApplicationConfig> applicationConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ApplicationConfig.class, false, false);
        if (applicationConfigMap != null && applicationConfigMap.size() > 0) {
            ApplicationConfig applicationConfig = null;
            for (ApplicationConfig config : applicationConfigMap.values()) {
                if (config.isDefault() == null || config.isDefault().booleanValue()) {
                    if (applicationConfig != null) {
                        throw new IllegalStateException("Duplicate application configs: " + applicationConfig + " and " + config);
                    }
                    applicationConfig = config;
                }
            }
            if (applicationConfig != null) {
                setApplication(applicationConfig);
            }
        }
    }
    if (getModule() == null
            && (getProvider() == null || getProvider().getModule() == null)) {
        Map<String, ModuleConfig> moduleConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ModuleConfig.class, false, false);
        if (moduleConfigMap != null && moduleConfigMap.size() > 0) {
            ModuleConfig moduleConfig = null;
            for (ModuleConfig config : moduleConfigMap.values()) {
                if (config.isDefault() == null || config.isDefault().booleanValue()) {
                    if (moduleConfig != null) {
                        throw new IllegalStateException("Duplicate module configs: " + moduleConfig + " and " + config);
                    }
                    moduleConfig = config;
                }
            }
            if (moduleConfig != null) {
                setModule(moduleConfig);
            }
        }
    }
    //<dubbo:registry address="zookeeper://localhost:2181" id="com.alibaba.dubbo.config.RegistryConfig" />
    //
    if ((getRegistries() == null || getRegistries().isEmpty())
            && (getProvider() == null || getProvider().getRegistries() == null || getProvider().getRegistries().isEmpty())
        //<dubbo:application name="demo-provider" id="demo-provider" />
            && (getApplication() == null || getApplication().getRegistries() == null || getApplication().getRegistries().isEmpty())) {
        //"com.alibaba.dubbo.config.RegistryConfig" -> "<dubbo:registry address="zookeeper://localhost:2181" id="com.alibaba.dubbo.config.RegistryConfig" />"
        Map<String, RegistryConfig> registryConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, RegistryConfig.class, false, false);
        if (registryConfigMap != null && registryConfigMap.size() > 0) {
            List<RegistryConfig> registryConfigs = new ArrayList<RegistryConfig>();
            for (RegistryConfig config : registryConfigMap.values()) {
                if (config.isDefault() == null || config.isDefault().booleanValue()) {
                    registryConfigs.add(config);
                }
            }
            if (registryConfigs != null && !registryConfigs.isEmpty()) {
                super.setRegistries(registryConfigs);
            }
        }
    }
    
    if (getMonitor() == null
            && (getProvider() == null || getProvider().getMonitor() == null)
            && (getApplication() == null || getApplication().getMonitor() == null)) {
        Map<String, MonitorConfig> monitorConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, MonitorConfig.class, false, false);
        if (monitorConfigMap != null && monitorConfigMap.size() > 0) {
            MonitorConfig monitorConfig = null;
            for (MonitorConfig config : monitorConfigMap.values()) {
                if (config.isDefault() == null || config.isDefault().booleanValue()) {
                    if (monitorConfig != null) {
                        throw new IllegalStateException("Duplicate monitor configs: " + monitorConfig + " and " + config);
                    }
                    monitorConfig = config;
                }
            }
            if (monitorConfig != null) {
                setMonitor(monitorConfig);
            }
        }
    }
    //dubbo:service没设置protocol，也没设置provider，或者设置了provider但是指向的dubbo:provider的protocols没设置
    if ((getProtocols() == null || getProtocols().isEmpty())
            && (getProvider() == null || getProvider().getProtocols() == null || getProvider().getProtocols().isEmpty())) {
        //拿"dubbo" -> "<dubbo:protocol name="dubbo" port="20880" id="dubbo" />"
        Map<String, ProtocolConfig> protocolConfigMap = applicationContext == null ? null : BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, ProtocolConfig.class, false, false);
        if (protocolConfigMap != null && protocolConfigMap.size() > 0) {
            List<ProtocolConfig> protocolConfigs = new ArrayList<ProtocolConfig>();
            for (ProtocolConfig config : protocolConfigMap.values()) {
                if (config.isDefault() == null || config.isDefault().booleanValue()) {
                    protocolConfigs.add(config);
                }
            }
            if (protocolConfigs != null && !protocolConfigs.isEmpty()) {
                super.setProtocols(protocolConfigs);
            }
        }
    }
    
    if (getPath() == null || getPath().length() == 0) {
        if (beanName != null && beanName.length() > 0
                && getInterface() != null && getInterface().length() > 0
                && beanName.startsWith(getInterface())) {
            //dubbo:service设置了path就用不然设置bean名为path com.alibaba.dubbo.demo.DemoService
            setPath(beanName);
        }
    }
    //先看dubbo:service有没有设置delay，没有则取dubbo:provider的delay，假如都没设置或者是-1则返回false
    if (!isDelay()) {
        //有delay则延迟delay秒调用doExport
        export();
    }
}

最后最重要的doExport

protected synchronized void doExport() {
    if (unexported) {
        throw new IllegalStateException("Already unexported!");
    }
    if (exported) {
        return;
    }
    exported = true;
    if (interfaceName == null || interfaceName.length() == 0) {
        throw new IllegalStateException("<dubbo:service interface=\"\" /> interface not allow null!");
    }
    checkDefault();
    if (provider != null) {
        if (application == null) {
            application = provider.getApplication();
        }
        if (module == null) {
            module = provider.getModule();
        }
        if (registries == null) {
            registries = provider.getRegistries();
        }
        if (monitor == null) {
            monitor = provider.getMonitor();
        }
        if (protocols == null) {
            protocols = provider.getProtocols();
        }
    }
    if (module != null) {
        if (registries == null) {
            registries = module.getRegistries();
        }
        if (monitor == null) {
            monitor = module.getMonitor();
        }
    }
    if (application != null) {
        if (registries == null) {
            registries = application.getRegistries();
        }
        if (monitor == null) {
            monitor = application.getMonitor();
        }
    }
    if (ref instanceof GenericService) {
        interfaceClass = GenericService.class;
        if (StringUtils.isEmpty(generic)) {
            generic = Boolean.TRUE.toString();
        }
    } else {
        try {
            //这里是最重要的地方，反射
            interfaceClass = Class.forName(interfaceName, true, Thread.currentThread()
                    .getContextClassLoader());
        } catch (ClassNotFoundException e) {
            throw new IllegalStateException(e.getMessage(), e);
        }
        checkInterfaceAndMethods(interfaceClass, methods);
        checkRef();
        generic = Boolean.FALSE.toString();
    }
    if (local != null) {
        if ("true".equals(local)) {
            local = interfaceName + "Local";
        }
        Class<?> localClass;
        try {
            localClass = ClassHelper.forNameWithThreadContextClassLoader(local);
        } catch (ClassNotFoundException e) {
            throw new IllegalStateException(e.getMessage(), e);
        }
        if (!interfaceClass.isAssignableFrom(localClass)) {
            throw new IllegalStateException("The local implementation class " + localClass.getName() + " not implement interface " + interfaceName);
        }
    }
    if (stub != null) {
        if ("true".equals(stub)) {
            stub = interfaceName + "Stub";
        }
        Class<?> stubClass;
        try {
            stubClass = ClassHelper.forNameWithThreadContextClassLoader(stub);
        } catch (ClassNotFoundException e) {
            throw new IllegalStateException(e.getMessage(), e);
        }
        if (!interfaceClass.isAssignableFrom(stubClass)) {
            throw new IllegalStateException("The stub implementation class " + stubClass.getName() + " not implement interface " + interfaceName);
        }
    }
    checkApplication();
    checkRegistry();
    checkProtocol();
    appendProperties(this);
    checkStubAndMock(interfaceClass);
    //服务发现的path，缺省为接口名
    if (path == null || path.length() == 0) {
        path = interfaceName;
    }
    //生成url   
  //  dubbo://172.17.8.254:20880/com.alibaba.dubbo.demo.DemoService?anyhost=true&application=demo-provider&bind.ip=172.17.8.254&bind.port=20880&channel.readonly.sent=true&codec=dubbo&dubbo=2.0.0&generic=false&heartbeat=60000&interface=com.alibaba.dubbo.demo.DemoService&methods=sayHello&pid=6755&qos.port=22222&side=provider&timestamp=1522308929779
    //host由this.findConfigedHosts(protocolConfig, registryURLs, map); 取 dubbo:protocol host，没有的话取本地ip 并且设置到bind.ip
     // port由this.findConfigedPorts(protocolConfig, name, map);取 dubbo:protocol port，没有的话取本地ip 并且设置到bind.port
    doExportUrls();
    //转化成ProviderModel注册
    ProviderModel providerModel = new ProviderModel(getUniqueServiceName(), this, ref);
    ApplicationModel.initProviderModel(getUniqueServiceName(), providerModel);
}

doExportUrlsFor1Protocol部分重要源码

    for (URL registryURL : registryURLs) {
        url = url.addParameterIfAbsent("dynamic", registryURL.getParameter("dynamic"));
        URL monitorUrl = loadMonitor(registryURL);
        if (monitorUrl != null) {
            url = url.addParameterAndEncoded(Constants.MONITOR_KEY, monitorUrl.toFullString());
        }
        if (logger.isInfoEnabled()) {
            logger.info("Register dubbo service " + interfaceClass.getName() + " url " + url + " to registry " + registryURL);
        }
        //通过动态代理工厂生成实现类调用器Invoker, Invoker相当于动态代理类
        // private static final ProxyFactory proxyFactory = ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension();
        //默认是JavassistProxyFactory
        //ref指的是service类这里就会被代理成一个Invoker类
        Invoker<?> invoker = proxyFactory.getInvoker(ref, (Class) interfaceClass, registryURL.addParameterAndEncoded(Constants.EXPORT_KEY, url.toFullString()));
        DelegateProviderMetaDataInvoker wrapperInvoker = new DelegateProviderMetaDataInvoker(invoker, this);
//private static final Protocol protocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension();
        //实际是DubboProtocol
        Exporter<?> exporter = protocol.export(wrapperInvoker);
        exporters.add(exporter);
    }

incubator-dubbo/dubbo-rpc/dubbo-rpc-api/src/main/resources/META-INF/dubbo/internal/com.alibaba.dubbo.rpc.ProxyFactory

stub=com.alibaba.dubbo.rpc.proxy.wrapper.StubProxyFactoryWrapper
jdk=com.alibaba.dubbo.rpc.proxy.jdk.JdkProxyFactory
javassist=com.alibaba.dubbo.rpc.proxy.javassist.JavassistProxyFactory

proxy 服务代理层

JavassistProxyFactory源码分析

public class JavassistProxyFactory extends AbstractProxyFactory {
    @SuppressWarnings("unchecked")
    public <T> T getProxy(Invoker<T> invoker, Class<?>[] interfaces) {
        return (T) Proxy.getProxy(interfaces).newInstance(new InvokerInvocationHandler(invoker));
    }

    public <T> Invoker<T> getInvoker(T proxy, Class<T> type, URL url) {
        // 包含'$'无法处理
        final Wrapper wrapper = Wrapper.getWrapper(proxy.getClass().getName().indexOf('$') < 0 ? proxy.getClass() : type);
        return new AbstractProxyInvoker<T>(proxy, type, url) {
            @Override
            protected Object doInvoke(T proxy, String methodName,
                                      Class<?>[] parameterTypes,
                                      Object[] arguments) throws Throwable {
                return wrapper.invokeMethod(proxy, methodName, parameterTypes, arguments);
            }
        };
    }
}

public abstract class AbstractProxyInvoker<T> implements Invoker<T> {

    private final T proxy;

    private final Class<T> type;

    private final URL url;

    public AbstractProxyInvoker(T proxy, Class<T> type, URL url) {
        if (proxy == null) {
            throw new IllegalArgumentException("proxy == null");
        }
        if (type == null) {
            throw new IllegalArgumentException("interface == null");
        }
        if (!type.isInstance(proxy)) {
            throw new IllegalArgumentException(proxy.getClass().getName() + " not implement interface " + type);
        }
        this.proxy = proxy;
        this.type = type;
        this.url = url;
    }

    public Class<T> getInterface() {
        return type;
    }

    public URL getUrl() {
        return url;
    }

    public boolean isAvailable() {
        return true;
    }

    public void destroy() {
    }

    public Result invoke(Invocation invocation) throws RpcException {
        try {
            return new RpcResult(doInvoke(proxy, invocation.getMethodName(), invocation.getParameterTypes(), invocation.getArguments()));
        } catch (InvocationTargetException e) {
            return new RpcResult(e.getTargetException());
        } catch (Throwable e) {
            throw new RpcException("Failed to invoke remote proxy method " + invocation.getMethodName() + " to " + getUrl() + ", cause: " + e.getMessage(), e);
        }
    }

    protected abstract Object doInvoke(T proxy, String methodName, Class<?>[] parameterTypes, Object[] arguments) throws Throwable;

    @Override
    public String toString() {
        return getInterface() + " -> " + (getUrl() == null ? " " : getUrl().toString());
    }

}

public class DelegateProviderMetaDataInvoker<T> implements Invoker {
    protected final Invoker<T> invoker;
    private ServiceConfig metadata;

    public DelegateProviderMetaDataInvoker(Invoker<T> invoker,ServiceConfig metadata) {
        this.invoker = invoker;
        this.metadata = metadata;
    }

    public Class<T> getInterface() {
        return invoker.getInterface();
    }

    public URL getUrl() {
        return invoker.getUrl();
    }

    public boolean isAvailable() {
        return invoker.isAvailable();
    }

    public Result invoke(Invocation invocation) throws RpcException {
        return invoker.invoke(invocation);
    }

    public void destroy() {
        invoker.destroy();
    }

    public ServiceConfig getMetadata() {
        return metadata;
    }
}

incubator-dubbo/dubbo-rpc/dubbo-rpc-dubbo/src/main/resources/META-INF/dubbo/internal/com.alibaba.dubbo.rpc.Protocol

dubbo=com.alibaba.dubbo.rpc.protocol.dubbo.DubboProtocol

protocol 远程调用层

DubboProtocol源码分析

public <T> Exporter<T> export(Invoker<T> invoker) throws RpcException {
    URL url = invoker.getUrl();

    // url转化为com.alibaba.dubbo.demo.DemoService:20880
    String key = serviceKey(url);
    //DelegateProviderMetaDataInvoker封装到DubboExporter
    DubboExporter<T> exporter = new DubboExporter<T>(invoker, key, exporterMap);
    //缓存起来，每次被调用的时候直接使用
    exporterMap.put(key, exporter);

    //export an stub service for dispatching event
    Boolean isStubSupportEvent = url.getParameter(Constants.STUB_EVENT_KEY, Constants.DEFAULT_STUB_EVENT);
    Boolean isCallbackservice = url.getParameter(Constants.IS_CALLBACK_SERVICE, false);
    if (isStubSupportEvent && !isCallbackservice) {
        String stubServiceMethods = url.getParameter(Constants.STUB_EVENT_METHODS_KEY);
        if (stubServiceMethods == null || stubServiceMethods.length() == 0) {
            if (logger.isWarnEnabled()) {
                logger.warn(new IllegalStateException("consumer [" + url.getParameter(Constants.INTERFACE_KEY) +
                        "], has set stubproxy support event ,but no stub methods founded."));
            }
        } else {
            stubServiceMethodsMap.put(url.getServiceKey(), stubServiceMethods);
        }
    }
//server = Exchangers.bind(url, requestHandler);
    openServer(url);
    optimizeSerialization(url);
    return exporter;
}

openServer最后是调用了server = Exchangers.bind(url, requestHandler)后文会详细说明

public class DubboExporter<T> extends AbstractExporter<T> {

    private final String key;

    private final Map<String, Exporter<?>> exporterMap;

    public DubboExporter(Invoker<T> invoker, String key, Map<String, Exporter<?>> exporterMap) {
        super(invoker);
        this.key = key;
        this.exporterMap = exporterMap;
    }

    @Override
    public void unexport() {
        super.unexport();
        exporterMap.remove(key);
    }

}

关于SPI可以参考

http://www1350.github.io/#post/114

Exporter

public interface Exporter<T> {

    /**
     * get invoker.
     *
     * @return invoker
     */
    Invoker<T> getInvoker();

    /**
     * unexport.
     * <p>
     * <code>
     * getInvoker().destroy();
     * </code>
     */
    void unexport();

}

Invoker

public interface Invoker<T> extends Node {

    /**
     * get service interface.
     *
     * @return service interface.
     */
    Class<T> getInterface();

    /**
     * invoke.
     *
     * @param invocation
     * @return result
     * @throws RpcException
     */
    Result invoke(Invocation invocation) throws RpcException;

}

public interface Node {

    /**
     * get url.
     *
     * @return url.
     */
    URL getUrl();

    /**
     * is available.
     *
     * @return available.
     */
    boolean isAvailable();

    /**
     * destroy.
     */
    void destroy();

}

sequencediagram133

Mar 29 '18 03:03 www1350

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dubbo源码解析（一）ServiceConfig

什么是Dubbo?

各层说明

启动demo

dubbo-demo-api

dubbo-demo-provider

dubbo-demo-consumer

xml解析分析

config 配置层

ServiceBean源码分析

proxy 服务代理层

JavassistProxyFactory源码分析

protocol 远程调用层

DubboProtocol源码分析

Exporter

Invoker

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