dubbo源码之消费端启动和调用

一.参考

dubbo的spi和生产端的服务导出的源码分析参考之前的帖子.

参考dubbo-2.7.x版本的源码

二.架构

三.测试用例

使用dubbo-demo包下dubbo-demo-xml-consumer包下的org.apache.dubbo.demo.consumer.Application#main测试方法.

测试用例如下：

public static void main(String[] args) throws Exception {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring/dubbo-consumer.xml");
        context.start();
//        DemoService demoService = context.getBean("demoService", DemoService.class);
        GreetingService greetingService = context.getBean("greetingService", GreetingService.class);

        new Thread(() -> {
            while (true) {
                String greetings = greetingService.hello();
                System.out.println(greetings + " from separated thread.");
                try {
                    //Thread.sleep(100);
                    TimeUnit.MINUTES.sleep(10);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }).start();
}

四.源码分析

(一)初始化代理类

进入方法AbstractApplicationContext#getBean().调用栈如下图

1.依次调用AbstractApplicationContext#getBean()->FactoryBeanRegistrySupport#doGetObjectFromFactoryBean->ReferenceBean#getObject->ReferenceConfig#init,代码如下图：方法逻辑和服务端导出服务类似.

public synchronized void init() {
        if (initialized) {
            return;
        }


        if (bootstrap == null) {
            bootstrap = DubboBootstrap.getInstance();
            // compatible with api call.
            if (null != this.getRegistries()) {
                bootstrap.registries(this.getRegistries());
            }
            // 初始化配置中心,元数据中心
            bootstrap.initialize();
        }

        checkAndUpdateSubConfigs();

        checkStubAndLocal(interfaceClass);
        ConfigValidationUtils.checkMock(interfaceClass, this);

        //map中隐含了应用,模块，接口，方法的上下级关系的覆盖.
        Map<String, String> map = new HashMap<String, String>();
        map.put(SIDE_KEY, CONSUMER_SIDE);

        ReferenceConfigBase.appendRuntimeParameters(map);
        if (!ProtocolUtils.isGeneric(generic)) {
            String revision = Version.getVersion(interfaceClass, version);
            if (revision != null && revision.length() > 0) {
                map.put(REVISION_KEY, revision);
            }

            String[] methods = Wrapper.getWrapper(interfaceClass).getMethodNames();
            if (methods.length == 0) {
                logger.warn("No method found in service interface " + interfaceClass.getName());
                map.put(METHODS_KEY, ANY_VALUE);
            } else {
                map.put(METHODS_KEY, StringUtils.join(new HashSet<String>(Arrays.asList(methods)), COMMA_SEPARATOR));
            }
        }
        map.put(INTERFACE_KEY, interfaceName);
        AbstractConfig.appendParameters(map, getMetrics());
        AbstractConfig.appendParameters(map, getApplication());
        AbstractConfig.appendParameters(map, getModule());
        // remove 'default.' prefix for configs from ConsumerConfig
        // appendParameters(map, consumer, Constants.DEFAULT_KEY);
        AbstractConfig.appendParameters(map, consumer);
        AbstractConfig.appendParameters(map, this);
        MetadataReportConfig metadataReportConfig = getMetadataReportConfig();
        if (metadataReportConfig != null && metadataReportConfig.isValid()) {
            map.putIfAbsent(METADATA_KEY, REMOTE_METADATA_STORAGE_TYPE);
        }
        Map<String, AsyncMethodInfo> attributes = null;
        if (CollectionUtils.isNotEmpty(getMethods())) {
            attributes = new HashMap<>();
            for (MethodConfig methodConfig : getMethods()) {