标签:reference names swa ant uid ebe bool nts 命名空间
1. 要了解Dubbo是如何解析标签的,首先要清楚一点就是Spring如何处理自定义标签的,因为Dubbo的标签可以算是Spring自定义标签的一种情况;
2. Spring通过两个接口来解析自定义的标签:NamespaceHandler和BeanDefinitionParser接口;NamespaceHandler负责namespace的处理,而BeanDefinitionParser负责Bean的解析;
3. 我们自定义标签的时候,可以实现NamespaceHandler接口,但更多的是继承NamespaceHandler的抽象类:NamespaceHandlerSupport,然后在classpath的META-INF目录下编写一个spring.handlers文件,在该文件中定义namespace的URL和namespace处理类的映射。
比如Dubbo的spring.handlers文件内容(/是转义):
http\://code.alibabatech.com/schema/dubbo=com.alibaba.dubbo.config.spring.schema.DubboNamespaceHandler
4. spring框架初始化时会加载所有classpath的spring.handlers文件,把namespace的URL和namespace处理类映射到Map中,Spring在解析的时候,遇到一些自定义的标签的时候,会在这个Map中查找namespace处理类,使用这个使用这个自定义的处理类来进行标签的解析工作;
5. 同样,Dubbo框架的namespace的处理类是DubboNamespaceHandler,也是实现了NamespaceHandlerSupport接口来处理命名空间,然后在这个类的初始化的时候给所有标签都注册了各自的解析器;而Dubbo的解析类DubboBeanDefinitionParser同样也是实现了BeanDefinitionParser接口;
DubboNamespaceHandler 源代码如此下:
/** * DubboNamespaceHandler * * @author william.liangf * @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)); } }
可以看到,Dubbo有10个标签,每个标签会解析到对应的实体上,每个实体中的属性对应标签中的属性,比如ApplicationConfig类:
/** * ApplicationConfig * * @author william.liangf * @export */ public class ApplicationConfig extends AbstractConfig { private static final long serialVersionUID = 5508512956753757169L; // 应用名称 private String name; // 模块版本 private String version; // 应用负责人 private String owner; // 组织名(BU或部门) private String organization; // 分层 private String architecture; // 环境,如:dev/test/run private String environment; // Java代码编译器 private String compiler; // 日志输出方式 private String logger; // 注册中心 private List<RegistryConfig> registries; // 服务监控 private MonitorConfig monitor; // 是否为缺省 private Boolean isDefault; public ApplicationConfig() { } public ApplicationConfig(String name) { setName(name); } @Parameter(key = Constants.APPLICATION_KEY, required = true) public String getName() { return name; } public void setName(String name) { checkName("name", name); this.name = name; if (id == null || id.length() == 0) { id = name; } } @Parameter(key = "application.version") public String getVersion() { return version; } public void setVersion(String version) { this.version = version; } public String getOwner() { return owner; } public void setOwner(String owner) { checkMultiName("owner", owner); this.owner = owner; } public String getOrganization() { return organization; } public void setOrganization(String organization) { checkName("organization", organization); this.organization = organization; } public String getArchitecture() { return architecture; } public void setArchitecture(String architecture) { checkName("architecture", architecture); this.architecture = architecture; } public String getEnvironment() { return environment; } public void setEnvironment(String environment) { checkName("environment", environment); if(environment != null) { if (! ("develop".equals(environment) || "test".equals(environment) || "product".equals(environment))) { throw new IllegalStateException("Unsupported environment: " + environment + ", only support develop/test/product, default is product."); } } this.environment = environment; } public RegistryConfig getRegistry() { return registries == null || registries.size() == 0 ? null : registries.get(0); } public void setRegistry(RegistryConfig registry) { List<RegistryConfig> registries = new ArrayList<RegistryConfig>(1); registries.add(registry); this.registries = registries; } public List<RegistryConfig> getRegistries() { return registries; } @SuppressWarnings({ "unchecked" }) public void setRegistries(List<? extends RegistryConfig> registries) { this.registries = (List<RegistryConfig>)registries; } public MonitorConfig getMonitor() { return monitor; } public void setMonitor(MonitorConfig monitor) { this.monitor = monitor; } public void setMonitor(String monitor) { this.monitor = new MonitorConfig(monitor); } public String getCompiler() { return compiler; } public void setCompiler(String compiler) { this.compiler = compiler; AdaptiveCompiler.setDefaultCompiler(compiler); } public String getLogger() { return logger; } public void setLogger(String logger) { this.logger = logger; LoggerFactory.setLoggerAdapter(logger); } public Boolean isDefault() { return isDefault; } public void setDefault(Boolean isDefault) { this.isDefault = isDefault; } }
Dubbo版本:2.8.4.5
标签:reference names swa ant uid ebe bool nts 命名空间
原文地址:http://www.cnblogs.com/xiaozhang2014/p/7821104.html