protected synchronized void doExport() {
    //如果是已经解除暴露的接口则抛出异常        if (unexported) {            throw new IllegalStateException("Already unexported!");        } 　　　　 //如果已经暴露则不需要重复暴露         if (exported) {            return;        }        exported = true;        if (interfaceName == null || interfaceName.length() == 0) {            throw new IllegalStateException("
      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();            }        }  // ref是接口实现类引用，GenericService是泛接口,这个方式主要用于服务器端没有API接口及模型类元的情况，参数及返回值中的所有POJO均用Map表示，通常用于框架集成，比如：实现一个通用的远程服务Mock框架，可通过实现GenericService接口处理所有服务请求。        if (ref instanceof GenericService) {            interfaceClass = GenericService.class;            if (StringUtils.isEmpty(generic)) {                generic = Boolean.TRUE.toString();            }        } else {            try {                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();        } 　　　　 //local属性已被弃用，由stub属性替代        if(local !=null){            if(local=="true"){                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 implemention class " + localClass.getName() + " not implement interface " + interfaceName);            }        }  //stub设为true，表示使用缺省代理类名，即：接口名 + Local后缀，服务接口客户端本地代理类名，用于在客户端执行本地逻辑，如本地缓存等，该本地代理类的构造函数必须允许传入远程代理对象，构造函数如：public XxxServiceLocal(XxxService xxxService)        if(stub !=null){            if(stub=="true"){                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 implemention class " + stubClass.getName() + " not implement interface " + interfaceName);            }        }        checkApplication();        checkRegistry();        checkProtocol();        appendProperties(this);        checkStubAndMock(interfaceClass);        if (path == null || path.length() == 0) {            path = interfaceName;        }        doExportUrls();    }

 在doExport方法中，对要暴露的服务进行了一系列的检查，检查provider，application，module，registries，monitor这些参数是否为空，是否是GenericService类型的服务，检查要注册的bean的引用和方法等。在方法的最后会调用doExportUrls方法。