案例介绍
本专栏通过三个章节来实现一共简单的rpc框架，用于深入学习rpc框架是如何通信的，当前章节主要介绍如何自定义xml文件并进行解析。想解析自定义的xml首先定义自己的xsd文件，并且实现spring的NamespaceHandlerSupport、BeanDefinitionParser，两个方法进行处理。
远程过程调用协议 RPC（Remote Procedure Call）—即远程过程调用，它是一种通过网络从远程计算机程序上请求服务，而不需要了解底层网络技术的协议。RPC协议假定某些传输协议的存在，如TCP或UDP，为通信程序之间携带信息数据。在OSI网络通信模型中，RPC跨越了传输层和应用层。RPC使得开发包括网络分布式多程序在内的应用程序更加容易。 RPC采用客户机/服务器模式。请求程序就是一个客户机，而服务提供程序就是一个服务器。首先，客户机调用进程发送一个有进程参数的调用信息到服务进程，然后等待应答信息。在服务器端，进程保持睡眠状态直到调用信息到达为止。当一个调用信息到达，服务器获得进程参数，计算结果，发送答复信息，然后等待下一个调用信息，最后，客户端调用进程接收答复信息，获得进程结果，然后调用执行继续进行。
Dubbo是 [1] 阿里巴巴公司开源的一个高性能优秀的服务框架，使得应用可通过高性能的 RPC 实现服务的输出和输入功能，可以和 [2] Spring框架无缝集成。 Dubbo是一款高性能、轻量级的开源Java RPC框架，它提供了三大核心能力：面向接口的远程方法调用，智能容错和负载均衡，以及服务自动注册和发现。
环境准备
- jdk 1.8.0
- IntelliJ IDEA Community Edition 2018.3.1 x64
代码示例
itcode-demo-rpc-01 └── src └── main │ ├── java │ │ └── org.itcode.demo.rpc.config │ │ ├── spring │ │ │ ├── bean │ │ │ │ ├── ConsumerBean.java │ │ │ │ ├── ProviderBean.java │ │ │ │ └── ServerBean.java │ │ │ ├── MyBeanDefinitionParser.java │ │ │ └── MyNamespaceHandler.java │ │ ├── ConsumerConfig.java │ │ ├── ProviderConfig.java │ │ └── ProviderConfig.java │ └── resource │ └── META-INF │ ├── rpc.xsd │ ├── spring.handlers │ └── spring.schemas └── test ├── java │ └── org.itcode.demo.test │ ├── service │ │ ├── impl │ │ │ └── HelloServiceImpl.java │ │ └── HelloService.java │ └── ApiTest.java └── resource ├── itcode-rpc-consumer.xml ├── itcode-rpc-provider.xml └── log4j.xml
ProviderConfig.java
/** * http://www.datalong.top * create by Datalong on 2021/5/4 * 本章节主要介绍服务生产者的配置 */ public class ProviderConfig { private String nozzle; //接口 private String ref; //映射 private String alias; //别名 //发布 protected void doExport() { System.out.format("生产者信息=> [接口：%s] [映射：%s] [别名：%s] \r\n", nozzle, ref, alias); } public String getNozzle() { return nozzle; } public void setNozzle(String nozzle) { this.nozzle = nozzle; } public String getRef() { return ref; } public void setRef(String ref) { this.ref = ref; } public String getAlias() { return alias; } public void setAlias(String alias) { this.alias = alias; } }
ProviderBean.java
public class ProviderBean extends ProviderConfig implements ApplicationContextAware { @Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { //服务生产者 doExport(); } }
MyBeanDefinitionParser.java
public class MyBeanDefinitionParser implements BeanDefinitionParser { private final Class<?> beanClass; MyBeanDefinitionParser(Class<?> beanClass) { this.beanClass = beanClass; } @Override public BeanDefinition parse(Element element, ParserContext parserContext) { RootBeanDefinition beanDefinition = new RootBeanDefinition(); beanDefinition.setBeanClass(beanClass); beanDefinition.setLazyInit(false); String beanName = element.getAttribute("id"); parserContext.getRegistry().registerBeanDefinition(beanName, beanDefinition); for (Method method : beanClass.getMethods()) { if (!isProperty(method, beanClass)) continue; String name = method.getName(); String methodName = name.substring(3, 4).toLowerCase() + name.substring(4); String value = element.getAttribute(methodName); beanDefinition.getPropertyValues().addPropertyValue(methodName, value); } return beanDefinition; } private boolean isProperty(Method method, Class beanClass) { String methodName = method.getName(); boolean flag = methodName.length() > 3 && methodName.startsWith("set") && Modifier.isPublic(method.getModifiers()) && method.getParameterTypes().length == 1; Method getter = null; if (!flag) return false; Class<?> type = method.getParameterTypes()[0]; try { getter = beanClass.getMethod("get" + methodName.substring(3)); } catch (NoSuchMethodException ignore) { } if (null == getter) { try { getter = beanClass.getMethod("is" + methodName.substring(3)); } catch (NoSuchMethodException ignore) { } } flag = getter != null && Modifier.isPublic(getter.getModifiers()) && type.equals(getter.getReturnType()); return flag; } }
MyNamespaceHandler.java
public class MyNamespaceHandler extends NamespaceHandlerSupport { @Override public void init() { registerBeanDefinitionParser("consumer", new MyBeanDefinitionParser(ConsumerBean.class)); registerBeanDefinitionParser("provider", new MyBeanDefinitionParser(ProviderBean.class)); registerBeanDefinitionParser("server", new MyBeanDefinitionParser(ServerBean.class)); } }
rpc.xsd
<?xml version="1.0" encoding="UTF-8"?> <xsd:schema xmlns="http://rpc.itcode.org/schema/rpc" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:beans="http://www.springframework.org/schema/beans" targetNamespace="http://rpc.itcode.org/schema/rpc" elementFormDefault="qualified" attributeFormDefault="unqualified"> <xsd:import namespace="http://www.springframework.org/schema/beans"/> <!-- org.itcode.demo.rpc.config.ServerConfig --> <xsd:element name="server"> <xsd:complexType> <xsd:complexContent> <xsd:extension base="beans:identifiedType"> <xsd:attribute name="host" type="xsd:string"> <xsd:annotation> <xsd:documentation><![CDATA[ 栈台地点 ]]></xsd:documentation> </xsd:annotation> </xsd:attribute> <xsd:attribute name="port" type="xsd:string"> <xsd:annotation> <xsd:documentation><![CDATA[ 栈台岸口 ]]></xsd:documentation> </xsd:annotation> </xsd:attribute> </xsd:extension> </xsd:complexContent> </xsd:complexType> </xsd:element> <!-- org.itcode.demo.rpc.config.ConsumerConfig --> <xsd:element name="consumer"> <xsd:complexType> <xsd:complexContent> <xsd:extension base="beans:identifiedType"> <xsd:attribute name="nozzle" type="xsd:string"> <xsd:annotation> <xsd:documentation><![CDATA[ 接口名称 ]]></xsd:documentation> </xsd:annotation> </xsd:attribute> <xsd:attribute name="alias" type="xsd:string"> <xsd:annotation> <xsd:documentation><![CDATA[ 服务别名分组信息 ]]></xsd:documentation> </xsd:annotation> </xsd:attribute> </xsd:extension> </xsd:complexContent> </xsd:complexType> </xsd:element> <!-- org.itcode.demo.rpc.config.ProviderConfig --> <xsd:element name="provider"> <xsd:complexType> <xsd:complexContent> <xsd:extension base="beans:identifiedType"> <xsd:attribute name="nozzle" type="xsd:string"> <xsd:annotation> <xsd:documentation><![CDATA[ 接口名称 ]]></xsd:documentation> </xsd:annotation> </xsd:attribute> <xsd:attribute name="ref" type="xsd:string"> <xsd:annotation> <xsd:documentation><![CDATA[ 接口实现类 ]]></xsd:documentation> </xsd:annotation> </xsd:attribute> <xsd:attribute name="alias" type="xsd:string"> <xsd:annotation> <xsd:documentation><![CDATA[ 服务别名分组信息 ]]></xsd:documentation> </xsd:annotation> </xsd:attribute> </xsd:extension> </xsd:complexContent> </xsd:complexType> </xsd:element> </xsd:schema>
spring.handlers
http\://rpc.itcode.org/schema/rpc=org.itcode.demo.rpc.config.spring.MyNamespaceHandler
spring.schemas
http\://rpc.itcode.org/schema/rpc/rpc.xsd=META-INF/rpc.xsd
测试部分
itcode-rpc-consumer.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:rpc="http://rpc.itcode.org/schema/rpc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://rpc.itcode.org/schema/rpc http://rpc.itcode.org/schema/rpc/rpc.xsd"> <!-- redis配置，保存链接 --> <rpc:server id="consumer_itstack" host="127.0.0.1" port="6379"/> <rpc:consumer id="consumer_helloService" nozzle="org.itcode.demo.test.service.HelloService" alias="itStackRpc"/> </beans>
itcode-rpc-provider.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:rpc="http://rpc.itcode.org/schema/rpc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://rpc.itcode.org/schema/rpc http://rpc.itcode.org/schema/rpc/rpc.xsd"> <rpc:provider id="provider_helloService" nozzle="org.itcode.demo.test.service.HelloService" ref="helloService" alias="itStackRpc" /> </beans>
ApiTest.java
package org.itcode.demo.test; import org.springframework.context.support.ClassPathXmlApplicationContext; /** * http://www.datalong.top * create by Datalong on 2021/5/4 * 本章节主要介绍如何读取自定义配置xml文件字段信息 */ public class ApiTest { public static void main(String[] args) { String[] configs = {"itcode-rpc-consumer.xml", "itcode-rpc-provider.xml"}; new ClassPathXmlApplicationContext(configs); } }
测试结果
2019-05-07 19:44:24,805 main INFO [org.springframework.context.support.ClassPathXmlApplicationContext:prepareRefresh:510] - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@299a06ac: startup date [Tue May 07 19:44:24 CST 2019]; root of context hierarchy 2019-05-07 19:44:24,872 main INFO [org.springframework.beans.factory.xml.XmlBeanDefinitionReader:loadBeanDefinitions:315] - Loading XML bean definitions from class path resource [itcode-rpc-consumer.xml] 2019-05-07 19:44:24,972 main INFO [org.springframework.beans.factory.xml.XmlBeanDefinitionReader:loadBeanDefinitions:315] - Loading XML bean definitions from class path resource [itcode-rpc-provider.xml] 2019-05-07 19:44:25,008 main INFO [org.springframework.beans.factory.support.DefaultListableBeanFactory:preInstantiateSingletons:577] - Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@192b07fd: defining beans [consumer_itstack,consumer_helloService,provider_helloService]; root of factory hierarchy 服务端信息=> [注册中心地址：127.0.0.1] [注册中心端口：6379] 生产者信息=> [接口：org.itcode.demo.test.service.HelloService] [映射：helloService] [别名：itStackRpc]
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