1、Dubbo源码解析--Dubbo如何驱动Spring IOC容器并配合工作的？

首先Spring要注入自己的bean需要在Spring-provider.xml(提供者spring注入文件，名字可能不一样)添加bean注入，其中有dubbo的自定义标签，xml如何识别这些标签？拿到标签如何注入到Spring Container？一般需要如下几个步骤：

　　1）、设计配置属性和JavaBean

　　　　设计属性即dubbo.xsd中的attribute属性，如下

　　　　

<dubbo:reference timeout="40000" check="false" id="order" interface="com.xx.order"
                     group="test" version="0.1" />

　　xsd定义这些属性，匹配JavaBean的属性，如下：

　　

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.alibaba.dubbo.config;

import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.URL;
import com.alibaba.dubbo.common.Version;
import com.alibaba.dubbo.common.bytecode.Wrapper;
import com.alibaba.dubbo.common.extension.ExtensionLoader;
import com.alibaba.dubbo.common.utils.ConfigUtils;
import com.alibaba.dubbo.common.utils.NetUtils;
import com.alibaba.dubbo.common.utils.ReflectUtils;
import com.alibaba.dubbo.common.utils.StringUtils;
import com.alibaba.dubbo.config.annotation.Reference;
import com.alibaba.dubbo.config.model.ApplicationModel;
import com.alibaba.dubbo.config.model.ConsumerModel;
import com.alibaba.dubbo.config.support.Parameter;
import com.alibaba.dubbo.rpc.Invoker;
import com.alibaba.dubbo.rpc.Protocol;
import com.alibaba.dubbo.rpc.ProxyFactory;
import com.alibaba.dubbo.rpc.StaticContext;
import com.alibaba.dubbo.rpc.cluster.Cluster;
import com.alibaba.dubbo.rpc.cluster.directory.StaticDirectory;
import com.alibaba.dubbo.rpc.cluster.support.AvailableCluster;
import com.alibaba.dubbo.rpc.cluster.support.ClusterUtils;
import com.alibaba.dubbo.rpc.protocol.injvm.InjvmProtocol;
import com.alibaba.dubbo.rpc.service.GenericService;
import com.alibaba.dubbo.rpc.support.ProtocolUtils;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import static com.alibaba.dubbo.common.utils.NetUtils.isInvalidLocalHost;

/**
 * ReferenceConfig
 *
 * @export
 */
public class ReferenceConfig<T> extends AbstractReferenceConfig {

    private static final long serialVersionUID = -5864351140409987595L;

    private static final Protocol refprotocol = ExtensionLoader.getExtensionLoader(Protocol.class).getAdaptiveExtension();

    private static final Cluster cluster = ExtensionLoader.getExtensionLoader(Cluster.class).getAdaptiveExtension();

    private static final ProxyFactory proxyFactory = ExtensionLoader.getExtensionLoader(ProxyFactory.class).getAdaptiveExtension();
    private final List<URL> urls = new ArrayList<URL>();
    // interface name
    private String interfaceName;
    private Class<?> interfaceClass;
    // client type
    private String client;
    // url for peer-to-peer invocation
    private String url;
    // method configs
    private List<MethodConfig> methods;
    // default config
    private ConsumerConfig consumer;
    private String protocol;
    // interface proxy reference
    private transient volatile T ref;
    private transient volatile Invoker<?> invoker;
    private transient volatile boolean initialized;
    private transient volatile boolean destroyed;
    @SuppressWarnings("unused")
    private final Object finalizerGuardian = new Object() {
        @Override
        protected void finalize() throws Throwable {
            super.finalize();

            if (!ReferenceConfig.this.destroyed) {
                logger.warn("ReferenceConfig(" + url + ") is not DESTROYED when FINALIZE");

                /* don't destroy for now
                try {
                    ReferenceConfig.this.destroy();
                } catch (Throwable t) {
                        logger.warn("Unexpected err when destroy invoker of ReferenceConfig(" + url + ") in finalize method!", t);
                }
                */
            }
        }
    };

    public ReferenceConfig() {
    }

    public ReferenceConfig(Reference reference) {
        appendAnnotation(Reference.class, reference);
    }

    private static void checkAndConvertImplicitConfig(MethodConfig method, Map<String, String> map, Map<Object, Object> attributes) {
        //check config conflict
        if (Boolean.FALSE.equals(method.isReturn()) && (method.getOnreturn() != null || method.getOnthrow() != null)) {
            throw new IllegalStateException("method config error : return attribute must be set true when onreturn or onthrow has been setted.");
        }
        //convert onreturn methodName to Method
        String onReturnMethodKey = StaticContext.getKey(map, method.getName(), Constants.ON_RETURN_METHOD_KEY);
        Object onReturnMethod = attributes.get(onReturnMethodKey);
        if (onReturnMethod != null && onReturnMethod instanceof String) {
            attributes.put(onReturnMethodKey, getMethodByName(method.getOnreturn().getClass(), onReturnMethod.toString()));
        }
        //convert onthrow methodName to Method
        String onThrowMethodKey = StaticContext.getKey(map, method.getName(), Constants.ON_THROW_METHOD_KEY);
        Object onThrowMethod = attributes.get(onThrowMethodKey);
        if (onThrowMethod != null && onThrowMethod instanceof String) {
            attributes.put(onThrowMethodKey, getMethodByName(method.getOnthrow().getClass(), onThrowMethod.toString()));
        }
        //convert oninvoke methodName to Method
        String onInvokeMethodKey = StaticContext.getKey(map, method.getName(), Constants.ON_INVOKE_METHOD_KEY);
        Object onInvokeMethod = attributes.get(onInvokeMethodKey);
        if (onInvokeMethod != null && onInvokeMethod instanceof String) {
            attributes.put(onInvokeMethodKey, getMethodByName(method.getOninvoke().getClass(), onInvokeMethod.toString()));
        }
    }

    private static Method getMethodByName(Class<?> clazz, String methodName) {
        try {
            return ReflectUtils.findMethodByMethodName(clazz, methodName);
        } catch (Exception e) {
            throw new IllegalStateException(e);
        }
    }

    public URL toUrl() {
        return urls == null || urls.isEmpty() ? null : urls.iterator().next();
    }

    public List<URL> toUrls() {
        return urls;
    }

    public synchronized T get() {
        if (destroyed) {
            throw new IllegalStateException("Already destroyed!");
        }
        if (ref == null) {
            init();
        }
        return ref;
    }

    public synchronized void destroy() {
        if (ref == null) {
            return;
        }
        if (destroyed) {
            return;
        }
        destroyed = true;
        try {
            invoker.destroy();
        } catch (Throwable t) {
            logger.warn("Unexpected err when destroy invoker of ReferenceConfig(" + url + ").", t);
        }
        invoker = null;
        ref = null;
    }

    private void init() {
        if (initialized) {
            return;
        }
        initialized = true;
        if (interfaceName == null || interfaceName.length() == 0) {
            throw new IllegalStateException("<dubbo:reference interface=\"\" /> interface not allow null!");
        }
        // get consumer's global configuration
        checkDefault();
        appendProperties(this);
        if (getGeneric() == null && getConsumer() != null) {
            setGeneric(getConsumer().getGeneric());
        }
        if (ProtocolUtils.isGeneric(getGeneric())) {
            interfaceClass = GenericService.class;
        } else {
            try {
                interfaceClass = Class.forName(interfaceName, true, Thread.currentThread()
                        .getContextClassLoader());
            } catch (ClassNotFoundException e) {
                throw new IllegalStateException(e.getMessage(), e);
            }
            checkInterfaceAndMethods(interfaceClass, methods);
        }
        String resolve = System.getProperty(interfaceName);
        String resolveFile = null;
        if (resolve == null || resolve.length() == 0) {
            resolveFile = System.getProperty("dubbo.resolve.file");
            if (resolveFile == null || resolveFile.length() == 0) {
                File userResolveFile = new File(new File(System.getProperty("user.home")), "dubbo-resolve.properties");
                if (userResolveFile.exists()) {
                    resolveFile = userResolveFile.getAbsolutePath();
                }
            }
            if (resolveFile != null && resolveFile.length() > 0) {
                Properties properties = new Properties();
                FileInputStream fis = null;
                try {
                    fis = new FileInputStream(new File(resolveFile));
                    properties.load(fis);
                } catch (IOException e) {
                    throw new IllegalStateException("Unload " + resolveFile + ", cause: " + e.getMessage(), e);
                } finally {
                    try {
                        if (null != fis) fis.close();
                    } catch (IOException e) {
                        logger.warn(e.getMessage(), e);
                    }
                }
                resolve = properties.getProperty(interfaceName);
            }
        }
        if (resolve != null && resolve.length() > 0) {
            url = resolve;
            if (logger.isWarnEnabled()) {
                if (resolveFile != null && resolveFile.length() > 0) {
                    logger.warn("Using default dubbo resolve file " + resolveFile + " replace " + interfaceName + "" + resolve + " to p2p invoke remote service.");
                } else {
                    logger.warn("Using -D" + interfaceName + "=" + resolve + " to p2p invoke remote service.");
                }
            }
        }
        if (consumer != null) {
            if (application == null) {
                application = consumer.getApplication();
            }
            if (module == null) {
                module = consumer.getModule();
            }
            if (registries == null) {
                registries = consumer.getRegistries();
            }
            if (monitor == null) {
                monitor = consumer.getMonitor();
            }
        }
        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();
            }
        }
        checkApplication();
        checkStubAndMock(interfaceClass);
        Map<String, String> map = new HashMap<String, String>();
        Map<Object, Object> attributes = new HashMap<Object, Object>();
        map.put(Constants.SIDE_KEY, Constants.CONSUMER_SIDE);
        map.put(Constants.DUBBO_VERSION_KEY, Version.getVersion());
        map.put(Constants.TIMESTAMP_KEY, String.valueOf(System.currentTimeMillis()));
        if (ConfigUtils.getPid() > 0) {
            map.put(Constants.PID_KEY, String.valueOf(ConfigUtils.getPid()));
        }
        if (!isGeneric()) {
            String revision = Version.getVersion(interfaceClass, version);
            if (revision != null && revision.length() > 0) {
                map.put("revision", revision);
            }

            String[] methods = Wrapper.getWrapper(interfaceClass).getMethodNames();
            if (methods.length == 0) {
                logger.warn("NO method found in service interface " + interfaceClass.getName());
                map.put("methods", Constants.ANY_VALUE);
            } else {
                map.put("methods", StringUtils.join(new HashSet<String>(Arrays.asList(methods)), ","));
            }
        }
        map.put(Constants.INTERFACE_KEY, interfaceName);
        appendParameters(map, application);
        appendParameters(map, module);
        appendParameters(map, consumer, Constants.DEFAULT_KEY);
        appendParameters(map, this);
        String prefix = StringUtils.getServiceKey(map);
        if (methods != null && !methods.isEmpty()) {
            for (MethodConfig method : methods) {
                appendParameters(map, method, method.getName());
                String retryKey = method.getName() + ".retry";
                if (map.containsKey(retryKey)) {
                    String retryValue = map.remove(retryKey);
                    if ("false".equals(retryValue)) {
                        map.put(method.getName() + ".retries", "0");
                    }
                }
                appendAttributes(attributes, method, prefix + "." + method.getName());
                checkAndConvertImplicitConfig(method, map, attributes);
            }
        }

        String hostToRegistry = ConfigUtils.getSystemProperty(Constants.DUBBO_IP_TO_REGISTRY);
        if (hostToRegistry == null || hostToRegistry.length() == 0) {
            hostToRegistry = NetUtils.getLocalHost();
        } else if (isInvalidLocalHost(hostToRegistry)) {
            throw new IllegalArgumentException("Specified invalid registry ip from property:" + Constants.DUBBO_IP_TO_REGISTRY + ", value:" + hostToRegistry);
        }
        map.put(Constants.REGISTER_IP_KEY, hostToRegistry);

        //attributes are stored by system context.
        StaticContext.getSystemContext().putAll(attributes);
        ref = createProxy(map);
        ConsumerModel consumerModel = new ConsumerModel(getUniqueServiceName(), this, ref, interfaceClass.getMethods());
        ApplicationModel.initConsumerModel(getUniqueServiceName(), consumerModel);
    }

    @SuppressWarnings({"unchecked", "rawtypes", "deprecation"})
    private T createProxy(Map<String, String> map) {
        URL tmpUrl = new URL("temp", "localhost", 0, map);
        final boolean isJvmRefer;
        if (isInjvm() == null) {
            if (url != null && url.length() > 0) { // if a url is specified, don't do local reference
                isJvmRefer = false;
            } else if (InjvmProtocol.getInjvmProtocol().isInjvmRefer(tmpUrl)) {
                // by default, reference local service if there is
                isJvmRefer = true;
            } else {
                isJvmRefer = false;
            }
        } else {
            isJvmRefer = isInjvm().booleanValue();
        }

        if (isJvmRefer) {
            URL url = new URL(Constants.LOCAL_PROTOCOL, NetUtils.LOCALHOST, 0, interfaceClass.getName()).addParameters(map);
            invoker = refprotocol.refer(interfaceClass, url);
            if (logger.isInfoEnabled()) {
                logger.info("Using injvm service " + interfaceClass.getName());
            }
        } else {
            if (url != null && url.length() > 0) { // user specified URL, could be peer-to-peer address, or register center's address.
                String[] us = Constants.SEMICOLON_SPLIT_PATTERN.split(url);
                if (us != null && us.length > 0) {
                    for (String u : us) {
                        URL url = URL.valueOf(u);
                        if (url.getPath() == null || url.getPath().length() == 0) {
                            url = url.setPath(interfaceName);
                        }
                        if (Constants.REGISTRY_PROTOCOL.equals(url.getProtocol())) {
                            urls.add(url.addParameterAndEncoded(Constants.REFER_KEY, StringUtils.toQueryString(map)));
                        } else {
                            urls.add(ClusterUtils.mergeUrl(url, map));
                        }
                    }
                }
            } else { // assemble URL from register center's configuration
                List<URL> us = loadRegistries(false);
                if (us != null && !us.isEmpty()) {
                    for (URL u : us) {
                        URL monitorUrl = loadMonitor(u);
                        if (monitorUrl != null) {
                            map.put(Constants.MONITOR_KEY, URL.encode(monitorUrl.toFullString()));
                        }
                        urls.add(u.addParameterAndEncoded(Constants.REFER_KEY, StringUtils.toQueryString(map)));
                    }
                }
                if (urls == null || urls.isEmpty()) {
                    throw new IllegalStateException("No such any registry to reference " + interfaceName + " on the consumer " + NetUtils.getLocalHost() + " use dubbo version " + Version.getVersion() + ", please config <dubbo:registry address=\"...\" /> to your spring config.");
                }
            }

            if (urls.size() == 1) {
                invoker = refprotocol.refer(interfaceClass, urls.get(0));
            } else {
                List<Invoker<?>> invokers = new ArrayList<Invoker<?>>();
                URL registryURL = null;
                for (URL url : urls) {
                    invokers.add(refprotocol.refer(interfaceClass, url));
                    if (Constants.REGISTRY_PROTOCOL.equals(url.getProtocol())) {
                        registryURL = url; // use last registry url
                    }
                }
                if (registryURL != null) { // registry url is available
                    // use AvailableCluster only when register's cluster is available
                    URL u = registryURL.addParameter(Constants.CLUSTER_KEY, AvailableCluster.NAME);
                    invoker = cluster.join(new StaticDirectory(u, invokers));
                } else { // not a registry url
                    invoker = cluster.join(new StaticDirectory(invokers));
                }
            }
        }

        Boolean c = check;
        if (c == null && consumer != null) {
            c = consumer.isCheck();
        }
        if (c == null) {
            c = true; // default true
        }
        if (c && !invoker.isAvailable()) {
            throw new IllegalStateException("Failed to check the status of the service " + interfaceName + ". No provider available for the service " + (group == null ? "" : group + "/") + interfaceName + (version == null ? "" : ":" + version) + " from the url " + invoker.getUrl() + " to the consumer " + NetUtils.getLocalHost() + " use dubbo version " + Version.getVersion());
        }
        if (logger.isInfoEnabled()) {
            logger.info("Refer dubbo service " + interfaceClass.getName() + " from url " + invoker.getUrl());
        }
        // create service proxy
        return (T) proxyFactory.getProxy(invoker);
    }

    private void checkDefault() {
        if (consumer == null) {
            consumer = new ConsumerConfig();
        }
        appendProperties(consumer);
    }

    public Class<?> getInterfaceClass() {
        if (interfaceClass != null) {
            return interfaceClass;
        }
        if (isGeneric()
                || (getConsumer() != null && getConsumer().isGeneric())) {
            return GenericService.class;
        }
        try {
            if (interfaceName != null && interfaceName.length() > 0) {
                this.interfaceClass = Class.forName(interfaceName, true, Thread.currentThread()
                        .getContextClassLoader());
            }
        } catch (ClassNotFoundException t) {
            throw new IllegalStateException(t.getMessage(), t);
        }
        return interfaceClass;
    }

    /**
     * @param interfaceClass
     * @see #setInterface(Class)
     * @deprecated
     */
    @Deprecated
    public void setInterfaceClass(Class<?> interfaceClass) {
        setInterface(interfaceClass);
    }

    public String getInterface() {
        return interfaceName;
    }

    public void setInterface(Class<?> interfaceClass) {
        if (interfaceClass != null && !interfaceClass.isInterface()) {
            throw new IllegalStateException("The interface class " + interfaceClass + " is not a interface!");
        }
        this.interfaceClass = interfaceClass;
        setInterface(interfaceClass == null ? null : interfaceClass.getName());
    }

    public void setInterface(String interfaceName) {
        this.interfaceName = interfaceName;
        if (id == null || id.length() == 0) {
            id = interfaceName;
        }
    }

    public String getClient() {
        return client;
    }

    public void setClient(String client) {
        checkName("client", client);
        this.client = client;
    }

    @Parameter(excluded = true)
    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public List<MethodConfig> getMethods() {
        return methods;
    }

    @SuppressWarnings("unchecked")
    public void setMethods(List<? extends MethodConfig> methods) {
        this.methods = (List<MethodConfig>) methods;
    }

    public ConsumerConfig getConsumer() {
        return consumer;
    }

    public void setConsumer(ConsumerConfig consumer) {
        this.consumer = consumer;
    }

    public String getProtocol() {
        return protocol;
    }

    public void setProtocol(String protocol) {
        this.protocol = protocol;
    }

    // just for test
    Invoker<?> getInvoker() {
        return invoker;
    }

    @Parameter(excluded = true)
    public String getUniqueServiceName() {
        StringBuilder buf = new StringBuilder();
        if (group != null && group.length() > 0) {
            buf.append(group).append("/");
        }
        buf.append(interfaceName);
        if (version != null && version.length() > 0) {
            buf.append(":").append(version);
        }
        return buf.toString();
    }

}

　　2）、编写XSD文件，全称就是XML Schema

　　　　　　------用来校验XML，定义一系列的语法来规范XML

　　　　　　对应的XSD文件如下：

　　　　　　这个文件在dubbo.xsd中

　　　　　　

<xsd:complexType name="referenceType">
        <xsd:complexContent>
            <xsd:extension base="abstractReferenceType">
                <xsd:choice minOccurs="0" maxOccurs="unbounded">
                    <xsd:element ref="method" minOccurs="0" maxOccurs="unbounded"/>
                    <xsd:element ref="parameter" minOccurs="0" maxOccurs="unbounded"/>
                </xsd:choice>
                <xsd:attribute name="interface" type="xsd:token" use="required">
                    <xsd:annotation>
                        <xsd:documentation><![CDATA[ The service interface class name. ]]></xsd:documentation>
                        <xsd:appinfo>
                            <tool:annotation>
                                <tool:expected-type type="java.lang.Class"/>
                            </tool:annotation>
                        </xsd:appinfo>
                    </xsd:annotation>
                </xsd:attribute>
                <xsd:attribute name="url" type="xsd:string" use="optional">
                    <xsd:annotation>
                        <xsd:documentation><![CDATA[ Provider list url. ]]></xsd:documentation>
                    </xsd:annotation>
                </xsd:attribute>
                <xsd:attribute name="client" type="xsd:string" use="optional">
                    <xsd:annotation>
                        <xsd:documentation><![CDATA[ Protocol transport client type. ]]></xsd:documentation>
                    </xsd:annotation>
                </xsd:attribute>
                <xsd:attribute name="consumer" type="xsd:string" use="optional">
                    <xsd:annotation>
                        <xsd:documentation><![CDATA[ Deprecated. Replace to reference-default. ]]></xsd:documentation>
                    </xsd:annotation>
                </xsd:attribute>
                <xsd:attribute name="protocol" type="xsd:string" use="optional">
                    <xsd:annotation>
                        <xsd:documentation><![CDATA[ The service protocol. ]]></xsd:documentation>
                    </xsd:annotation>
                </xsd:attribute>
                <xsd:anyAttribute namespace="##other" processContents="lax"/>
            </xsd:extension>
        </xsd:complexContent>
    </xsd:complexType>

　　3）、编写NamespaceHandler和BeanDefinitionParser完成解析工作

　　　　编写继承自Spring的NamespaceHandlerSupport类，重写init（）方法，机械属性文件（spring-provider.xml  dubbo bean注入文件），如下：

　　　　

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.alibaba.dubbo.config.spring.schema;

import com.alibaba.dubbo.common.Version;
import com.alibaba.dubbo.config.*;
import com.alibaba.dubbo.config.spring.ReferenceBean;
import com.alibaba.dubbo.config.spring.ServiceBean;
import org.springframework.beans.factory.xml.NamespaceHandlerSupport;

/**
 * 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 AnnotationBeanDefinitionParser());
    }

}

　　4）、编写spring.handlers和spring.schemas串联起所有部件

　　　　spring.handlers文件如下，告诉springdubbo的处理类在哪里

　　　　

http\://code.alibabatech.com/schema/dubbo=com.alibaba.dubbo.config.spring.schema.DubboNamespaceHandler

　　　　spring.schemas文件如下，定义属性：

　　　　

http\://code.alibabatech.com/schema/dubbo/dubbo.xsd=META-INF/dubbo.xsd

　　　　这两个文件分别位于dubbo源码的如下路径：dubbo\dubbo-config\dubbo-config-spring\src\main\resources\META-INF

　　5）在Bean文件中应用

　　　　这里就是用ClassPathXmlApplicationContext读取Spring-provider.xml注入bean到Spring容器，然后在Service中通过@Resource或@Autowired注解拿到Bean使用。

其实大体流程如下：

　　1）入口是ClassPathXmlApplicationContext，这个我们一般会讲dubbo的提供者和消费者统一跟spring普通注入xml文件放在一块交由spring容器去解析，至于dubbo自定义标签如何解析往下看。

　　2）Spring会寻找spring.handlers和spring.schemas串联起所有部件，这里也就是dubbo.xsd已经dubbo自定义注解解析器DubboNamespaceHandler，dubbo.xsd负责解析spring-provider.xml配置的属性是否合法。DubboNamespaceHandler就能解析ClassPathXmlApplicationContext读入的spring-provider.xml读入的带有dubbo自定义标签的注入内容，然后通过DubboBeanDefinitionParser的parse方法进行解析并注入到Spring容器。

　　3）最后在Service或其他层面用@Resource 和 @Autowired等注解从Spring容器中取出使用。

　　至于dubbo的bean注入到spring容器中如何用netty进行通信、序列化、服务治理，后续会进行补充！