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spring4以上版本与dubbo兼容问题

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        Dubbo本身就是基于Spring环境的，但是Dubbo当年Spring才2.版本。 而现如今Spring 已经发展到4.3.，今年（2017）应该会发布Spring 5。而随着Spring Boot的大热，Java-Base方式配置Spring也变得越来越流行。Dubbo + Boot的开发模式，也是较为常见的组合方式。但是，当使用Dubbo在高版本Spring环境中使用注解方式配置时，会因为一些代码版本的原因导致整合出现问题。

1. Dubbo原生的注解配置

Dubbo本身就是基于Spring的，而且原生就提供注解配置：

服务提供方配置：

<!-- 扫描注解包路径，多个包用逗号分隔，不填pacakge表示扫描当前ApplicationContext中所有的类 --><dubbo:annotation package="com.foo.bar.service" />
服务提供方注解：
import com.alibaba.dubbo.config.annotation.Service;@Service(version="1.0.0")public class FooServiceImpl implements FooService {    // ......}
服务消费方注解：
import com.alibaba.dubbo.config.annotation.Reference;import org.springframework.stereotype.Component;@Componentpublic class BarAction {    @Reference(version="1.0.0")    private FooService fooService;}

服务消费方配置：
<!-- 扫描注解包路径，多个包用逗号分隔，不填pacakge表示扫描当前ApplicationContext中所有的类 --><dubbo:annotation package="com.foo.bar.action" />

通过官方的例子，就可以看出Dubbo使用xml配置<dubbo:annotation /> 来开启注解配置，并提供com.alibaba.dubbo.config.annotation.Service注解进行服务注册，提供com.alibaba.dubbo.config.annotation.Reference注解进行服务注入。
2.实现机制
可以看出，内部机制都是依托于<dubbo:annotation />标签。 通过源码分析，Dubbo对于Spring xml解析处理由com.alibaba.dubbo.config.spring.schema.DubboNamespaceHandler提供：
DubboNamespaceHandler.java
package com.alibaba.dubbo.config.spring.schema;import org.springframework.beans.factory.xml.NamespaceHandlerSupport;import com.alibaba.dubbo.common.Version;import com.alibaba.dubbo.config.ApplicationConfig;import com.alibaba.dubbo.config.ConsumerConfig;import com.alibaba.dubbo.config.ModuleConfig;import com.alibaba.dubbo.config.MonitorConfig;import com.alibaba.dubbo.config.ProtocolConfig;import com.alibaba.dubbo.config.ProviderConfig;import com.alibaba.dubbo.config.RegistryConfig;import com.alibaba.dubbo.config.spring.AnnotationBean;import com.alibaba.dubbo.config.spring.ReferenceBean;import com.alibaba.dubbo.config.spring.ServiceBean;/** * DubboNamespaceHandler *  * @export */public class DubboNamespaceHandler extends NamespaceHandlerSupport {    static {        Version.checkDuplicate(DubboNamespaceHandler.class);    }    public void init() {        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 DubboBeanDefinitionParser(AnnotationBean.class, true));    }}

通过上面的代码可以很直观的发现，<dubbo:annotation />标签实际是由com.alibaba.dubbo.config.spring.schema.DubboBeanDefinitionParser解析：
DubboBeanDefinitionParser.java
/** * AbstractBeanDefinitionParser *  * @export */public class DubboBeanDefinitionParser implements BeanDefinitionParser {    private static final Logger logger = LoggerFactory.getLogger(DubboBeanDefinitionParser.class);    private final Class<?> beanClass;    private final boolean required;    public DubboBeanDefinitionParser(Class<?> beanClass, boolean required) {        this.beanClass = beanClass;        this.required = required;    }    public BeanDefinition parse(Element element, ParserContext parserContext) {        return parse(element, parserContext, beanClass, required);    }    @SuppressWarnings("unchecked")    private static BeanDefinition parse(Element element, ParserContext parserContext, Class<?> beanClass, boolean required) {        //略    }

可以看到这个类实现了Spring的org.springframework.beans.factory.xml.BeanDefinitionParser接口，从而完成Spring Bean的解析工作。
而registerBeanDefinitionParser("annotation", new DubboBeanDefinitionParser(AnnotationBean.class, true));就是将<dubbo:annotation />标签，解析成com.alibaba.dubbo.config.spring.AnnotationBean并注册到Spring中。
3.AnnotationBean分析
先来看看源码：
AnnotationBean.java
package com.alibaba.dubbo.config.spring;/** * AnnotationBean *  * @export */public class AnnotationBean extends AbstractConfig implements DisposableBean, BeanFactoryPostProcessor, BeanPostProcessor, ApplicationContextAware {    private static final long serialVersionUID = -7582802454287589552L;    private static final Logger logger = LoggerFactory.getLogger(Logger.class);    private String annotationPackage;    private String[] annotationPackages;    private final Set<ServiceConfig<?>> serviceConfigs = new ConcurrentHashSet<ServiceConfig<?>>();    private final ConcurrentMap<String, ReferenceBean<?>> referenceConfigs = new ConcurrentHashMap<String, ReferenceBean<?>>();    public String getPackage() {        return annotationPackage;    }    public void setPackage(String annotationPackage) {        this.annotationPackage = annotationPackage;        this.annotationPackages = (annotationPackage == null || annotationPackage.length() == 0) ? null                : Constants.COMMA_SPLIT_PATTERN.split(annotationPackage);    }    private ApplicationContext applicationContext;    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {        this.applicationContext = applicationContext;    }    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)            throws BeansException {        if (annotationPackage == null || annotationPackage.length() == 0) {            return;        }        if (beanFactory instanceof BeanDefinitionRegistry) {            try {                // init scanner                Class<?> scannerClass = ReflectUtils.forName("org.springframework.context.annotation.ClassPathBeanDefinitionScanner");                Object scanner = scannerClass.getConstructor(new Class<?>[] {BeanDefinitionRegistry.class, boolean.class}).newInstance(new Object[] {(BeanDefinitionRegistry) beanFactory, true});                // add filter                Class<?> filterClass = ReflectUtils.forName("org.springframework.core.type.filter.AnnotationTypeFilter");                Object filter = filterClass.getConstructor(Class.class).newInstance(Service.class);                Method addIncludeFilter = scannerClass.getMethod("addIncludeFilter", ReflectUtils.forName("org.springframework.core.type.filter.TypeFilter"));                addIncludeFilter.invoke(scanner, filter);                // scan packages                String[] packages = Constants.COMMA_SPLIT_PATTERN.split(annotationPackage);                Method scan = scannerClass.getMethod("scan", new Class<?>[]{String[].class});                scan.invoke(scanner, new Object[] {packages});            } catch (Throwable e) {                // spring 2.0            }        }    }    public void destroy() throws Exception {        for (ServiceConfig<?> serviceConfig : serviceConfigs) {            try {                serviceConfig.unexport();            } catch (Throwable e) {                logger.error(e.getMessage(), e);            }        }        for (ReferenceConfig<?> referenceConfig : referenceConfigs.values()) {            try {                referenceConfig.destroy();            } catch (Throwable e) {                logger.error(e.getMessage(), e);            }        }    }    public Object postProcessAfterInitialization(Object bean, String beanName)            throws BeansException {        if (! isMatchPackage(bean)) {            return bean;        }        Service service = bean.getClass().getAnnotation(Service.class);        if (service != null) {            ServiceBean<Object> serviceConfig = new ServiceBean<Object>(service);            if (void.class.equals(service.interfaceClass())                    && "".equals(service.interfaceName())) {                if (bean.getClass().getInterfaces().length > 0) {                    serviceConfig.setInterface(bean.getClass().getInterfaces()[0]);                } else {                    throw new IllegalStateException("Failed to export remote service class " + bean.getClass().getName() + ", cause: The @Service undefined interfaceClass or interfaceName, and the service class unimplemented any interfaces.");                }            }            if (applicationContext != null) {                serviceConfig.setApplicationContext(applicationContext);                if (service.registry() != null && service.registry().length > 0) {                    List<RegistryConfig> registryConfigs = new ArrayList<RegistryConfig>();                    for (String registryId : service.registry()) {                        if (registryId != null && registryId.length() > 0) {                            registryConfigs.add((RegistryConfig)applicationContext.getBean(registryId, RegistryConfig.class));                        }                    }                    serviceConfig.setRegistries(registryConfigs);                }                if (service.provider() != null && service.provider().length() > 0) {                    serviceConfig.setProvider((ProviderConfig)applicationContext.getBean(service.provider(),ProviderConfig.class));                }                if (service.monitor() != null && service.monitor().length() > 0) {                    serviceConfig.setMonitor((MonitorConfig)applicationContext.getBean(service.monitor(), MonitorConfig.class));                }                if (service.application() != null && service.application().length() > 0) {                    serviceConfig.setApplication((ApplicationConfig)applicationContext.getBean(service.application(), ApplicationConfig.class));                }                if (service.module() != null && service.module().length() > 0) {                    serviceConfig.setModule((ModuleConfig)applicationContext.getBean(service.module(), ModuleConfig.class));                }                if (service.provider() != null && service.provider().length() > 0) {                    serviceConfig.setProvider((ProviderConfig)applicationContext.getBean(service.provider(), ProviderConfig.class));                } else {                }                if (service.protocol() != null && service.protocol().length > 0) {                    List<ProtocolConfig> protocolConfigs = new ArrayList<ProtocolConfig>();                    for (String protocolId : service.registry()) {                        if (protocolId != null && protocolId.length() > 0) {                            protocolConfigs.add((ProtocolConfig)applicationContext.getBean(protocolId, ProtocolConfig.class));                        }                    }                    serviceConfig.setProtocols(protocolConfigs);                }                try {                    serviceConfig.afterPropertiesSet();                } catch (RuntimeException e) {                    throw (RuntimeException) e;                } catch (Exception e) {                    throw new IllegalStateException(e.getMessage(), e);                }            }            serviceConfig.setRef(bean);            serviceConfigs.add(serviceConfig);            serviceConfig.export();        }        return bean;    }    public Object postProcessBeforeInitialization(Object bean, String beanName)            throws BeansException {        if (! isMatchPackage(bean)) {            return bean;        }        Method[] methods = bean.getClass().getMethods();        for (Method method : methods) {            String name = method.getName();            if (name.length() > 3 && name.startsWith("set")                    && method.getParameterTypes().length == 1                    && Modifier.isPublic(method.getModifiers())                    && ! Modifier.isStatic(method.getModifiers())) {                try {                    Reference reference = method.getAnnotation(Reference.class);                    if (reference != null) {                        Object value = refer(reference, method.getParameterTypes()[0]);                        if (value != null) {                            method.invoke(bean, new Object[] {  });                        }                    }                } catch (Throwable e) {                    logger.error("Failed to init remote service reference at method " + name + " in class " + bean.getClass().getName() + ", cause: " + e.getMessage(), e);                }            }        }        Field[] fields = bean.getClass().getDeclaredFields();        for (Field field : fields) {            try {                if (! field.isAccessible()) {                    field.setAccessible(true);                }                Reference reference = field.getAnnotation(Reference.class);                if (reference != null) {                    Object value = refer(reference, field.getType());                    if (value != null) {                        field.set(bean, value);                    }                }            } catch (Throwable e) {                logger.error("Failed to init remote service reference at filed " + field.getName() + " in class " + bean.getClass().getName() + ", cause: " + e.getMessage(), e);            }        }        return bean;    }    private Object refer(Reference reference, Class<?> referenceClass) { //method.getParameterTypes()[0]        String interfaceName;        if (! "".equals(reference.interfaceName())) {            interfaceName = reference.interfaceName();        } else if (! void.class.equals(reference.interfaceClass())) {            interfaceName = reference.interfaceClass().getName();        } else if (referenceClass.isInterface()) {            interfaceName = referenceClass.getName();        } else {            throw new IllegalStateException("The @Reference undefined interfaceClass or interfaceName, and the property type " + referenceClass.getName() + " is not a interface.");        }        String key = reference.group() + "/" + interfaceName + ":" + reference.version();        ReferenceBean<?> referenceConfig = referenceConfigs.get(key);        if (referenceConfig == null) {            referenceConfig = new ReferenceBean<Object>(reference);            if (void.class.equals(reference.interfaceClass())                    && "".equals(reference.interfaceName())                    && referenceClass.isInterface()) {                referenceConfig.setInterface(referenceClass);            }            if (applicationContext != null) {                referenceConfig.setApplicationContext(applicationContext);                if (reference.registry() != null && reference.registry().length > 0) {                    List<RegistryConfig> registryConfigs = new ArrayList<RegistryConfig>();                    for (String registryId : reference.registry()) {                        if (registryId != null && registryId.length() > 0) {                            registryConfigs.add((RegistryConfig)applicationContext.getBean(registryId, RegistryConfig.class));                        }                    }                    referenceConfig.setRegistries(registryConfigs);                }                if (reference.consumer() != null && reference.consumer().length() > 0) {                    referenceConfig.setConsumer((ConsumerConfig)applicationContext.getBean(reference.consumer(), ConsumerConfig.class));                }                if (reference.monitor() != null && reference.monitor().length() > 0) {                    referenceConfig.setMonitor((MonitorConfig)applicationContext.getBean(reference.monitor(), MonitorConfig.class));                }                if (reference.application() != null && reference.application().length() > 0) {                    referenceConfig.setApplication((ApplicationConfig)applicationContext.getBean(reference.application(), ApplicationConfig.class));                }                if (reference.module() != null && reference.module().length() > 0) {                    referenceConfig.setModule((ModuleConfig)applicationContext.getBean(reference.module(), ModuleConfig.class));                }                if (reference.consumer() != null && reference.consumer().length() > 0) {                    referenceConfig.setConsumer((ConsumerConfig)applicationContext.getBean(reference.consumer(), ConsumerConfig.class));                }                try {                    referenceConfig.afterPropertiesSet();                } catch (RuntimeException e) {                    throw (RuntimeException) e;                } catch (Exception e) {                    throw new IllegalStateException(e.getMessage(), e);                }            }            referenceConfigs.putIfAbsent(key, referenceConfig);            referenceConfig = referenceConfigs.get(key);        }        return referenceConfig.get();    }    private boolean isMatchPackage(Object bean) {        if (annotationPackages == null || annotationPackages.length == 0) {            return true;        }        String beanClassName = bean.getClass().getName();        for (String pkg : annotationPackages) {            if (beanClassName.startsWith(pkg)) {                return true;            }        }        return false;    }}

这个AnnotationBean实现了几个Spring生命周期接口，从而完成Dubbo整合Spring 的操作。
org.springframework.beans.factory.config.BeanFactoryPostProcessor
先来看看Spring文档中的介绍：
BeanFactoryPostProcessor operates on the bean configuration metadata; that is, the Spring IoC container allows a BeanFactoryPostProcessor to read the configuration metadata and potentially change it before the container instantiates any beans other than BeanFactoryPostProcessors.BeanFactoryPostProcessor可以用于在Spring IoC容器实例化Bean之前，对Spring Bean配置信息进行一些操作。

通过Spring文档，可以清楚这个接口的功能，那再来看看Dubbo的AnnotationBean是如何实现这个接口的：
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)            throws BeansException {        if (annotationPackage == null || annotationPackage.length() == 0) {            return;        }        if (beanFactory instanceof BeanDefinitionRegistry) {            try {                // init scanner                Class<?> scannerClass = ReflectUtils.forName("org.springframework.context.annotation.ClassPathBeanDefinitionScanner");                Object scanner = scannerClass.getConstructor(new Class<?>[] {BeanDefinitionRegistry.class, boolean.class}).newInstance(new Object[] {(BeanDefinitionRegistry) beanFactory, true});                // add filter                Class<?> filterClass = ReflectUtils.forName("org.springframework.core.type.filter.AnnotationTypeFilter");                Object filter = filterClass.getConstructor(Class.class).newInstance(Service.class);                Method addIncludeFilter = scannerClass.getMethod("addIncludeFilter", ReflectUtils.forName("org.springframework.core.type.filter.TypeFilter"));                addIncludeFilter.invoke(scanner, filter);                // scan packages                String[] packages = Constants.COMMA_SPLIT_PATTERN.split(annotationPackage);                Method scan = scannerClass.getMethod("scan", new Class<?>[]{String[].class});                scan.invoke(scanner, new Object[] {packages});            } catch (Throwable e) {                // spring 2.0            }        }    }
源码中已经标出了，Dubbo做了以下几件事：
  • 增加了一个class扫描器，用于处理Dubbo服务类的扫描
  • 增加过滤器，只扫描带有com.alibaba.dubbo.config.annotation.Service注解的class
  • 指定扫描的包，对应这<dubbo:annotation package="com.foo.bar.service" />标签中的package属性。
这个扫描器，就是将那些带有com.alibaba.dubbo.config.annotation.Service注解的class纳入Spring容器中，而这些Dubbo服务类上不需要单独加上Spring的注解，也不需要额外配置Spring Bean定义。
org.springframework.beans.factory.DisposableBean
再来看看这个接口，还是先看看Spring文档：
Implementing the org.springframework.beans.factory.DisposableBean interface allows a bean to get a callback when the container containing it is destroyed. The DisposableBean interface specifies a single method:void destroy() throws Exception;

这个接口实际上就是当Spring容器要销毁时的一个回调接口。
那再来看看Dubbo是如何实现的：
public void destroy() throws Exception {        for (ServiceConfig<?> serviceConfig : serviceConfigs) {            try {                serviceConfig.unexport();            } catch (Throwable e) {                logger.error(e.getMessage(), e);            }        }        for (ReferenceConfig<?> referenceConfig : referenceConfigs.values()) {            try {                referenceConfig.destroy();            } catch (Throwable e) {                logger.error(e.getMessage(), e);            }        }    }

也比较简单，实际上就是当Spring容器销毁时，对Dubbo服务进行反注册操作。
org.springframework.beans.factory.config.BeanPostProcessor
最后来看看这个接口，照例先看看Spring文档：
The BeanPostProcessor interface defines callback methods that you can implement to provide your own (or override the container’s default) instantiation logic, dependency-resolution logic, and so forth. If you want to implement some custom logic after the Spring container finishes instantiating, configuring, and initializing a bean, you can plug in one or more BeanPostProcessor implementations.

这个接口也是一个回调接口，只是回调时机不同，它发生在Spring容器初始化过程中，Bean实例化前后之时。也可以理解为Spring容器初始化完成后，Bean实例化前后但还没有给容器外使用前。
再来看看Dubbbo在这个时间点上做了什么：
public Object postProcessBeforeInitialization(Object bean, String beanName)            throws BeansException {        if (! isMatchPackage(bean)) {            return bean;        }        Method[] methods = bean.getClass().getMethods();        for (Method method : methods) {            String name = method.getName();            if (name.length() > 3 && name.startsWith("set")                    && method.getParameterTypes().length == 1                    && Modifier.isPublic(method.getModifiers())                    && ! Modifier.isStatic(method.getModifiers())) {                try {                    Reference reference = method.getAnnotation(Reference.class);                    if (reference != null) {                        Object value = refer(reference, method.getParameterTypes()[0]);                        if (value != null) {                            method.invoke(bean, new Object[] {  });                        }                    }                } catch (Throwable e) {                    logger.error("Failed to init remote service reference at method " + name + " in class " + bean.getClass().getName() + ", cause: " + e.getMessage(), e);                }            }        }        Field[] fields = bean.getClass().getDeclaredFields();        for (Field field : fields) {            try {                if (! field.isAccessible()) {                    field.setAccessible(true);                }                Reference reference = field.getAnnotation(Reference.class);                if (reference != null) {                    Object value = refer(reference, field.getType());                    if (value != null) {                        field.set(bean, value);                    }                }            } catch (Throwable e) {                logger.error("Failed to init remote service reference at filed " + field.getName() + " in class " + bean.getClass().getName() + ", cause: " + e.getMessage(), e);            }        }        return bean;    }

postProcessBeforeInitialization方法，顾名思义，发生Bean实例化之前。 通过源码就可以发现，主要用于处理Bean中的com.alibaba.dubbo.config.annotation.Reference注解，从而让Dubbo服务能够注入到Bean中。期间利用JAVA反射机制对Bean的方法和属性进行注入。
public Object postProcessAfterInitialization(Object bean, String beanName)            throws BeansException {        if (! isMatchPackage(bean)) {            return bean;        }        Service service = bean.getClass().getAnnotation(Service.class);        if (service != null) {            ServiceBean<Object> serviceConfig = new ServiceBean<Object>(service);            if (void.class.equals(service.interfaceClass())                    && "".equals(service.interfaceName())) {                if (bean.getClass().getInterfaces().length > 0) {                    serviceConfig.setInterface(bean.getClass().getInterfaces()[0]);                } else {                    throw new IllegalStateException("Failed to export remote service class " + bean.getClass().getName() + ", cause: The @Service undefined interfaceClass or interfaceName, and the service class unimplemented any interfaces.");                }            }            if (applicationContext != null) {                serviceConfig.setApplicationContext(applicationContext);                if (service.registry() != null && service.registry().length > 0) {                    List<RegistryConfig> registryConfigs = new ArrayList<RegistryConfig>();                    for (String registryId : service.registry()) {                        if (registryId != null && registryId.length() > 0) {                            registryConfigs.add((RegistryConfig)applicationContext.getBean(registryId, RegistryConfig.class));                        }                    }                    serviceConfig.setRegistries(registryConfigs);                }                if (service.provider() != null && service.provider().length() > 0) {                    serviceConfig.setProvider((ProviderConfig)applicationContext.getBean(service.provider(),ProviderConfig.class));                }                if (service.monitor() != null && service.monitor().length() > 0) {                    serviceConfig.setMonitor((MonitorConfig)applicationContext.getBean(service.monitor(), MonitorConfig.class));                }                if (service.application() != null && service.application().length() > 0) {                    serviceConfig.setApplication((ApplicationConfig)applicationContext.getBean(service.application(), ApplicationConfig.class));                }                if (service.module() != null && service.module().length() > 0) {                    serviceConfig.setModule((ModuleConfig)applicationContext.getBean(service.module(), ModuleConfig.class));                }                if (service.provider() != null && service.provider().length() > 0) {                    serviceConfig.setProvider((ProviderConfig)applicationContext.getBean(service.provider(), ProviderConfig.class));                } else {                }                if (service.protocol() != null && service.protocol().length > 0) {                    List<ProtocolConfig> protocolConfigs = new ArrayList<ProtocolConfig>();                    for (String protocolId : service.registry()) {                        if (protocolId != null && protocolId.length() > 0) {                            protocolConfigs.add((ProtocolConfig)applicationContext.getBean(protocolId, ProtocolConfig.class));                        }                    }                    serviceConfig.setProtocols(protocolConfigs);                }                try {                    serviceConfig.afterPropertiesSet();                } catch (RuntimeException e) {                    throw (RuntimeException) e;                } catch (Exception e) {                    throw new IllegalStateException(e.getMessage(), e);                }            }            serviceConfig.setRef(bean);            serviceConfigs.add(serviceConfig);            serviceConfig.export();        }        return bean;    }

postProcessAfterInitialization方法，同样从名字就能看出，其发生在Bean实例化之后。 通过源码就能发现，其作用就是将带有com.alibaba.dubbo.config.annotation.Service注解的Bean自动注册到Dubbo的注册中心，完成服务注册动作。
4.问题分析
通过上面的分析，对于Dubbo注解方式整合到Spring已经比较清楚了。 而在使用高版本Spring时，上面的AnnotationBean会出现一些问题。
问题主要集中在：
  1. Dubbo的注解Service有时不能进行服务注册
  2. Dubbo的注解Reference有时不能注入服务
从代码分析问题主要集中在postProcessBeforeInitialization和postProcessAfterInitialization方法上。
Service service = bean.getClass().getAnnotation(Service.class);
Method[] methods = bean.getClass().getMethods();
方法中都是利用Java反射来处理Bean的Class。
众所周知，Spring有两大利器IOC和AOP。在早期AOP基本都是利用JAVA动态代理实现的，而随着字节码技术的发展，现在Spring已经基本以ASM为代表的字节码增强框架为基础实现AOP,以及一些Bean的代理。
有兴趣的小伙伴可以打开spring-core-x.x.x.jar,会发现spring已经内嵌了asm以及cglib （org.springframework.asm）（org.springframework.cglib）
而在Spring环境中大量出现经过Cglib增强的Class，这些Class不在是简单的基于接口的代理机制了，其内部大量使用委派方式，以及访问器模式。最常见的就是Spring的事物，对于使用了@Transactional的Bean，都是以这种方式来增加事物处理能力的。
那基于这种方式扩展的Class，再通过反射getClass得到的是经过cglib改写后的class。在这些class上getAnnotation以及getMethods都不在是预期中的结果了。
所以，这也也就导致了上面罗列的两个问题。
5. 解决方案
经过对问题的分析，可以发现，问题主要是集中在Dubbo获取Bean的class上。
在Spring中，提供了很多Utils类。其中org.springframework.aop.support.AopUtils就可以用来对Aop代理的类进行操作的API。
于是，我们可以利用这个类来完成Class的获取。
于是，我们可以利用这个类来完成Class的获取。
private Class<?> getBeanClass(Object bean) {        Class<?> clazz = bean.getClass();        if (AopUtils.isAopProxy(bean)) {            clazz = AopUtils.getTargetClass(bean);        }        return clazz;    }
这样获取Class就可以这样：
Class<?> clazz = getBeanClass(bean);        Service service = clazz.getAnnotation(Service.class);
Class<?> clazz = getBeanClass(bean);
修改后完整的代码：
AnnotationBean.java
/* * Copyright 1999-2012 Alibaba Group. *   * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at *   *      http://www.apache.org/licenses/LICENSE-2.0 *   * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package com.roc.dubbo.config.spring;import java.lang.reflect.Field;import java.lang.reflect.Method;import java.lang.reflect.Modifier;import java.util.ArrayList;import java.util.List;import java.util.Set;import java.util.concurrent.ConcurrentHashMap;import java.util.concurrent.ConcurrentMap;import org.springframework.aop.support.AopUtils;import org.springframework.beans.BeansException;import org.springframework.beans.factory.DisposableBean;import org.springframework.beans.factory.config.BeanFactoryPostProcessor;import org.springframework.beans.factory.config.BeanPostProcessor;import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;import org.springframework.beans.factory.support.BeanDefinitionRegistry;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;import com.alibaba.dubbo.common.Constants;import com.alibaba.dubbo.common.logger.Logger;import com.alibaba.dubbo.common.logger.LoggerFactory;import com.alibaba.dubbo.common.utils.ConcurrentHashSet;import com.alibaba.dubbo.common.utils.ReflectUtils;import com.alibaba.dubbo.config.AbstractConfig;import com.alibaba.dubbo.config.ApplicationConfig;import com.alibaba.dubbo.config.ConsumerConfig;import com.alibaba.dubbo.config.ModuleConfig;import com.alibaba.dubbo.config.MonitorConfig;import com.alibaba.dubbo.config.ProtocolConfig;import com.alibaba.dubbo.config.ProviderConfig;import com.alibaba.dubbo.config.ReferenceConfig;import com.alibaba.dubbo.config.RegistryConfig;import com.alibaba.dubbo.config.ServiceConfig;import com.alibaba.dubbo.config.annotation.Reference;import com.alibaba.dubbo.config.annotation.Service;import com.alibaba.dubbo.config.spring.ReferenceBean;import com.alibaba.dubbo.config.spring.ServiceBean;/** * AnnotationBean *  * @export *  *         >>>修复@com.alibaba.dubbo.config.annotation.Service *         与Spring @Transactional 冲突 */public class AnnotationBean extends AbstractConfig        implements DisposableBean, BeanFactoryPostProcessor, BeanPostProcessor, ApplicationContextAware {    private static final long serialVersionUID = -7582802454287589552L;    private static final Logger logger = LoggerFactory.getLogger(Logger.class);    private String annotationPackage;    private String[] annotationPackages;    private final Set<ServiceConfig<?>> serviceConfigs = new ConcurrentHashSet<ServiceConfig<?>>();    private final ConcurrentMap<String, ReferenceBean<?>> referenceConfigs = new ConcurrentHashMap<String, ReferenceBean<?>>();    public String getPackage() {        return annotationPackage;    }    public void setPackage(String annotationPackage) {        this.annotationPackage = annotationPackage;        this.annotationPackages = (annotationPackage == null || annotationPackage.length() == 0) ? null                : Constants.COMMA_SPLIT_PATTERN.split(annotationPackage);    }    private ApplicationContext applicationContext;    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {        this.applicationContext = applicationContext;    }    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {        if (annotationPackage == null || annotationPackage.length() == 0) {            logger.debug("未定义注解扫描包");            return;        }        logger.info("扫描：" + annotationPackage);        if (beanFactory instanceof BeanDefinitionRegistry) {            try {                // init scanner                Class<?> scannerClass = ReflectUtils                        .forName("org.springframework.context.annotation.ClassPathBeanDefinitionScanner");                Object scanner = scannerClass                        .getConstructor(new Class<?>[] { BeanDefinitionRegistry.class, boolean.class })                        .newInstance(new Object[] { (BeanDefinitionRegistry) beanFactory, true });                // add filter                Class<?> filterClass = ReflectUtils                        .forName("org.springframework.core.type.filter.AnnotationTypeFilter");                Object filter = filterClass.getConstructor(Class.class).newInstance(Service.class);                Method addIncludeFilter = scannerClass.getMethod("addIncludeFilter",                        ReflectUtils.forName("org.springframework.core.type.filter.TypeFilter"));                addIncludeFilter.invoke(scanner, filter);                // scan packages                String[] packages = Constants.COMMA_SPLIT_PATTERN.split(annotationPackage);                Method scan = scannerClass.getMethod("scan", new Class<?>[] { String[].class });                scan.invoke(scanner, new Object[] { packages });            } catch (Throwable e) {                // spring 2.0            }        }    }    public void destroy() throws Exception {        for (ServiceConfig<?> serviceConfig : serviceConfigs) {            try {                serviceConfig.unexport();            } catch (Throwable e) {                logger.error(e.getMessage(), e);            }        }        for (ReferenceConfig<?> referenceConfig : referenceConfigs.values()) {            try {                referenceConfig.destroy();            } catch (Throwable e) {                logger.error(e.getMessage(), e);            }        }    }    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {        if (!isMatchPackage(bean)) {            return bean;        }        Class<?> clazz = getBeanClass(bean);        Service service = clazz.getAnnotation(Service.class);        // >>>>>>>>>>>>>>>>>>        if (service != null) {            ServiceBean<Object> serviceConfig = new ServiceBean<Object>(service);            if (void.class.equals(service.interfaceClass()) && "".equals(service.interfaceName())) {                if (bean.getClass().getInterfaces().length > 0) {                    serviceConfig.setInterface(bean.getClass().getInterfaces()[0]);                } else {                    throw new IllegalStateException("Failed to export remote service class " + bean.getClass().getName()                            + ", cause: The @Service undefined interfaceClass or interfaceName, and the service class unimplemented any interfaces.");                }            }            if (applicationContext != null) {                serviceConfig.setApplicationContext(applicationContext);                if (service.registry() != null && service.registry().length > 0) {                    List<RegistryConfig> registryConfigs = new ArrayList<RegistryConfig>();                    for (String registryId : service.registry()) {                        if (registryId != null && registryId.length() > 0) {                            registryConfigs                                    .add((RegistryConfig) applicationContext.getBean(registryId, RegistryConfig.class));                        }                    }                    serviceConfig.setRegistries(registryConfigs);                }                if (service.provider() != null && service.provider().length() > 0) {                    serviceConfig.setProvider(                            (ProviderConfig) applicationContext.getBean(service.provider(), ProviderConfig.class));                }                if (service.monitor() != null && service.monitor().length() > 0) {                    serviceConfig.setMonitor(                            (MonitorConfig) applicationContext.getBean(service.monitor(), MonitorConfig.class));                }                if (service.application() != null && service.application().length() > 0) {                    serviceConfig.setApplication((ApplicationConfig) applicationContext.getBean(service.application(),                            ApplicationConfig.class));                }                if (service.module() != null && service.module().length() > 0) {                    serviceConfig                            .setModule((ModuleConfig) applicationContext.getBean(service.module(), ModuleConfig.class));                }                if (service.provider() != null && service.provider().length() > 0) {                    serviceConfig.setProvider(                            (ProviderConfig) applicationContext.getBean(service.provider(), ProviderConfig.class));                } else {                }                if (service.protocol() != null && service.protocol().length > 0) {                    List<ProtocolConfig> protocolConfigs = new ArrayList<ProtocolConfig>();                    for (String protocolId : service.registry()) {                        if (protocolId != null && protocolId.length() > 0) {                            protocolConfigs                                    .add((ProtocolConfig) applicationContext.getBean(protocolId, ProtocolConfig.class));                        }                    }                    serviceConfig.setProtocols(protocolConfigs);                }                try {                    serviceConfig.afterPropertiesSet();                } catch (RuntimeException e) {                    throw (RuntimeException) e;                } catch (Exception e) {                    throw new IllegalStateException(e.getMessage(), e);                }            }            serviceConfig.setRef(bean);            serviceConfigs.add(serviceConfig);            serviceConfig.export();        }        return bean;    }    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {        // logger.debug("扫描bean:"+bean);        // System.out.println("扫描bean:"+bean);        if (!isMatchPackage(bean)) {            return bean;        }        // >>>>>>>>>>>>>>>>>>>>>>>>        Class<?> clazz = getBeanClass(bean);        // >>>>>>>>>>>>>>>>>>>>>>>>        Method[] methods = clazz.getMethods();        for (Method method : methods) {            String name = method.getName();            if (name.length() > 3 && name.startsWith("set") && method.getParameterTypes().length == 1                    && Modifier.isPublic(method.getModifiers()) && !Modifier.isStatic(method.getModifiers())) {                try {                    Reference reference = method.getAnnotation(Reference.class);                    if (reference != null) {                        Object value = refer(reference, method.getParameterTypes()[0]);                        if (value != null) {                            method.invoke(bean, new Object[] {});                        }                    }                } catch (Throwable e) {                    logger.error("Failed to init remote service reference at method " + name + " in class "                            + bean.getClass().getName() + ", cause: " + e.getMessage(), e);                }            }        }        // >>>>>>>>>>>>>>>>>>>>>>>>        Field[] fields = clazz.getDeclaredFields();        for (Field field : fields) {            try {                if (!field.isAccessible()) {                    field.setAccessible(true);                }                Reference reference = field.getAnnotation(Reference.class);                if (reference != null) {                    Object value = refer(reference, field.getType());                    if (value != null) {                        field.set(bean, value);                    }                }            } catch (Throwable e) {                logger.error("Failed to init remote service reference at filed " + field.getName() + " in class "                        + bean.getClass().getName() + ", cause: " + e.getMessage(), e);            }        }        return bean;    }    private Object refer(Reference reference, Class<?> referenceClass) { // method.getParameterTypes()[0]        String interfaceName;        if (!"".equals(reference.interfaceName())) {            interfaceName = reference.interfaceName();        } else if (!void.class.equals(reference.interfaceClass())) {            interfaceName = reference.interfaceClass().getName();        } else if (referenceClass.isInterface()) {            interfaceName = referenceClass.getName();        } else {            throw new IllegalStateException(                    "The @Reference undefined interfaceClass or interfaceName, and the property type "                            + referenceClass.getName() + " is not a interface.");        }        String key = reference.group() + "/" + interfaceName + ":" + reference.version();        ReferenceBean<?> referenceConfig = referenceConfigs.get(key);        if (referenceConfig == null) {            referenceConfig = new ReferenceBean<Object>(reference);            if (void.class.equals(reference.interfaceClass()) && "".equals(reference.interfaceName())                    && referenceClass.isInterface()) {                referenceConfig.setInterface(referenceClass);            }            if (applicationContext != null) {                referenceConfig.setApplicationContext(applicationContext);                if (reference.registry() != null && reference.registry().length > 0) {                    List<RegistryConfig> registryConfigs = new ArrayList<RegistryConfig>();                    for (String registryId : reference.registry()) {                        if (registryId != null && registryId.length() > 0) {                            registryConfigs                                    .add((RegistryConfig) applicationContext.getBean(registryId, RegistryConfig.class));                        }                    }                    referenceConfig.setRegistries(registryConfigs);                }                if (reference.consumer() != null && reference.consumer().length() > 0) {                    referenceConfig.setConsumer(                            (ConsumerConfig) applicationContext.getBean(reference.consumer(), ConsumerConfig.class));                }                if (reference.monitor() != null && reference.monitor().length() > 0) {                    referenceConfig.setMonitor(                            (MonitorConfig) applicationContext.getBean(reference.monitor(), MonitorConfig.class));                }                if (reference.application() != null && reference.application().length() > 0) {                    referenceConfig.setApplication((ApplicationConfig) applicationContext                            .getBean(reference.application(), ApplicationConfig.class));                }                if (reference.module() != null && reference.module().length() > 0) {                    referenceConfig.setModule(                            (ModuleConfig) applicationContext.getBean(reference.module(), ModuleConfig.class));                }                if (reference.consumer() != null && reference.consumer().length() > 0) {                    referenceConfig.setConsumer(                            (ConsumerConfig) applicationContext.getBean(reference.consumer(), ConsumerConfig.class));                }                try {                    referenceConfig.afterPropertiesSet();                } catch (RuntimeException e) {                    throw (RuntimeException) e;                } catch (Exception e) {                    throw new IllegalStateException(e.getMessage(), e);                }            }            referenceConfigs.putIfAbsent(key, referenceConfig);            referenceConfig = referenceConfigs.get(key);        }        return referenceConfig.get();    }    private boolean isMatchPackage(Object bean) {        if (annotationPackages == null || annotationPackages.length == 0) {            return true;        }        Class<?> clazz = getBeanClass(bean);        String beanClassName = clazz.getName();        for (String pkg : annotationPackages) {            if (beanClassName.startsWith(pkg)) {                return true;            }        }        return false;    }    private Class<?> getBeanClass(Object bean) {        Class<?> clazz = bean.getClass();        if (AopUtils.isAopProxy(bean)) {            clazz = AopUtils.getTargetClass(bean);        }        return clazz;    }}

6. 整合
同样，我不太赞同自己修改Dubbo源码，然后打包。倾入性太强。 通过前面几节的分析发现，其实只要AnnotationBean能够注册到Spring环境就行。而AnnotationBean无所谓放在哪个jar中。
所以，完全把修改后的AnnotationBean打入到自己写的jar中，然后注入Spring环境，以外挂的方式完成修改。
下面示例代码展示了，在Spring Boot中以外挂方式整合：
/** *  */package com.roc.dubbo.boot.configuration;import org.apache.logging.log4j.LogManager;import org.apache.logging.log4j.Logger;import com.roc.dubbo.config.spring.AnnotationBean;import org.springframework.boot.autoconfigure.AutoConfigureAfter;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.Import;/** * @date 2016年4月7日 下午4:36:19 * @description */@Configuration@Import(DubboBasicConfiguration.class)@AutoConfigureAfter(DubboBasicConfiguration.class)public class DubboConfiguration {    private final Logger logger = LogManager.getLogger(getClass());    @Bean    // @DependsOn("dubboConfiguration")    public AnnotationBean dubboAnnotationBean() {        AnnotationBean annotationBean = new AnnotationBean();        // annotationBean.setApplicationContext(applicationContext);        // annotationBean.setPackage(dubboProperties.getAnnotationPackage());        // annotationBean.setPackage("com.roc.pay");        logger.info("加入自定义" + annotationBean);        return annotationBean;    }}





                                             
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