手写RPC框架第一章《自定义配置xml》

2021-11-24 09:47:29

案例介绍

本案例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）—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

1、jdk 1.8.0

2、IntelliJ IDEA Community Edition 2018.3.1 x64

代码示例

1itstack-demo-rpc-01
 2└── src
 3    └── main
 4    │    ├── java
 5    │    │   └── org.itstack.demo.rpc.config
 6    │    │        ├── spring
 7    │    │        │   ├── bean
 8    │    │        │   │   ├── ConsumerBean.java
 9    │    │        │   │   ├── ProviderBean.java
10    │    │        │   │   └── ServerBean.java 
11    │    │        │   ├── MyBeanDefinitionParser.java    
12    │    │        │   └── MyNamespaceHandler.java
13    │    │        ├── ConsumerConfig.java    
14    │    │        ├── ProviderConfig.java    
15    │    │        └── ProviderConfig.java    
16    │      └── resource
17    │        └── META-INF
18    │            ├── rpc.xsd
19    │            ├── spring.handlers
20    │            └── spring.schemas    
21    └── test
22         ├── java
23         │   └── org.itstack.demo.test
24         │       ├── service
25         │       │   ├── impl
26         │        │   │   └── HelloServiceImpl.java  
27         │        │   └── HelloService.java
28         │       └── ApiTest.java                 
29         └── resource  
30             ├── itstack-rpc-consumer.xml         
31             ├── itstack-rpc-provider.xml
32             └── log4j.xml

ProviderConfig.java

1public class ProviderConfig {
 2
 3    private String nozzle; //接口
 4    private String ref;    //映射
 5    private String alias;  //别名
 6
 7    //发布
 8    protected void doExport() {
 9        System.out.format("生产者信息=> [接口：%s] [映射：%s] [别名：%s] \r\n", nozzle, ref, alias);
10    }
11
12    public String getNozzle() {
13        return nozzle;
14    }
15
16    public void setNozzle(String nozzle) {
17        this.nozzle = nozzle;
18    }
19
20    public String getRef() {
21        return ref;
22    }
23
24    public void setRef(String ref) {
25        this.ref = ref;
26    }
27
28    public String getAlias() {
29        return alias;
30    }
31
32    public void setAlias(String alias) {
33        this.alias = alias;
34    }
35}

ProviderBean.java

1public class ProviderBean extends ProviderConfig implements ApplicationContextAware {
2
3    @Override
4    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
5        //发布生产者
6        doExport();
7    }
8
9}

MyBeanDefinitionParser.java

1public class MyBeanDefinitionParser implements BeanDefinitionParser {
 2
 3    private final Class<?> beanClass;
 4
 5    MyBeanDefinitionParser(Class<?> beanClass) {
 6        this.beanClass = beanClass;
 7    }
 8
 9    @Override
10    public BeanDefinition parse(Element element, ParserContext parserContext) {
11
12        RootBeanDefinition beanDefinition = new RootBeanDefinition();
13        beanDefinition.setBeanClass(beanClass);
14        beanDefinition.setLazyInit(false);
15        String beanName = element.getAttribute("id");
16        parserContext.getRegistry().registerBeanDefinition(beanName, beanDefinition);
17
18        for (Method method : beanClass.getMethods()) {
19            if (!isProperty(method, beanClass)) continue;
20            String name = method.getName();
21            String methodName = name.substring(3, 4).toLowerCase() + name.substring(4);
22            String value = element.getAttribute(methodName);
23            beanDefinition.getPropertyValues().addPropertyValue(methodName, value);
24        }
25
26        return beanDefinition;
27    }
28
29    private boolean isProperty(Method method, Class beanClass) {
30
31        String methodName = method.getName();
32        boolean flag = methodName.length() > 3 && methodName.startsWith("set") && Modifier.isPublic(method.getModifiers()) && method.getParameterTypes().length == 1;
33        Method getter = null;
34        if (!flag) return false;
35
36        Class<?> type = method.getParameterTypes()[0];
37        try {
38            getter = beanClass.getMethod("get" + methodName.substring(3));
39        } catch (NoSuchMethodException ignore) {
40
41        }
42
43        if (null == getter) {
44            try {
45                getter = beanClass.getMethod("is" + methodName.substring(3));
46            } catch (NoSuchMethodException ignore) {
47
48            }
49        }
50
51        flag = getter != null && Modifier.isPublic(getter.getModifiers()) && type.equals(getter.getReturnType());
52
53        return flag;
54
55    }
56
57}

MyNamespaceHandler.java

1public class MyNamespaceHandler extends NamespaceHandlerSupport {
 2
 3    @Override
 4    public void init() {
 5        registerBeanDefinitionParser("consumer", new MyBeanDefinitionParser(ConsumerBean.class));
 6        registerBeanDefinitionParser("provider", new MyBeanDefinitionParser(ProviderBean.class));
 7        registerBeanDefinitionParser("server", new MyBeanDefinitionParser(ServerBean.class));
 8    }
 9
10}

rpc.xsd

1<?xml version="1.0" encoding="UTF-8"?>
 2<xsd:schema xmlns="http://rpc.itstack.org/schema/rpc"
 3            xmlns:xsd="http://www.w3.org/2001/XMLSchema"
 4            xmlns:beans="http://www.springframework.org/schema/beans"
 5            targetNamespace="http://rpc.itstack.org/schema/rpc"
 6            elementFormDefault="qualified" attributeFormDefault="unqualified">
 7    <xsd:import namespace="http://www.springframework.org/schema/beans"/>
 8
 9    <!-- org.itstack.demo.rpc.config.ServerConfig -->
10    <xsd:element name="server">
11        <xsd:complexType>
12            <xsd:complexContent>
13                <xsd:extension base="beans:identifiedType">
14                    <xsd:attribute name="host" type="xsd:string">
15                        <xsd:annotation>
16                            <xsd:documentation><![CDATA[ 栈台地点 ]]></xsd:documentation>
17                        </xsd:annotation>
18                    </xsd:attribute>
19                    <xsd:attribute name="port" type="xsd:string">
20                        <xsd:annotation>
21                            <xsd:documentation><![CDATA[ 栈台岸口  ]]></xsd:documentation>
22                        </xsd:annotation>
23                    </xsd:attribute>
24                </xsd:extension>
25            </xsd:complexContent>
26        </xsd:complexType>
27    </xsd:element>
28
29    <!-- org.itstack.demo.rpc.config.ConsumerConfig -->
30    <xsd:element name="consumer">
31        <xsd:complexType>
32            <xsd:complexContent>
33                <xsd:extension base="beans:identifiedType">
34                    <xsd:attribute name="nozzle" type="xsd:string">
35                        <xsd:annotation>
36                            <xsd:documentation><![CDATA[ 接口名称 ]]></xsd:documentation>
37                        </xsd:annotation>
38                    </xsd:attribute>
39                    <xsd:attribute name="alias" type="xsd:string">
40                        <xsd:annotation>
41                            <xsd:documentation><![CDATA[ 服务别名分组信息  ]]></xsd:documentation>
42                        </xsd:annotation>
43                    </xsd:attribute>
44                </xsd:extension>
45            </xsd:complexContent>
46        </xsd:complexType>
47    </xsd:element>
48
49    <!-- org.itstack.demo.rpc.config.ProviderConfig -->
50    <xsd:element name="provider">
51        <xsd:complexType>
52            <xsd:complexContent>
53                <xsd:extension base="beans:identifiedType">
54                    <xsd:attribute name="nozzle" type="xsd:string">
55                        <xsd:annotation>
56                            <xsd:documentation><![CDATA[ 接口名称 ]]></xsd:documentation>
57                        </xsd:annotation>
58                    </xsd:attribute>
59                    <xsd:attribute name="ref" type="xsd:string">
60                        <xsd:annotation>
61                            <xsd:documentation><![CDATA[ 接口实现类  ]]></xsd:documentation>
62                        </xsd:annotation>
63                    </xsd:attribute>
64                    <xsd:attribute name="alias" type="xsd:string">
65                        <xsd:annotation>
66                            <xsd:documentation><![CDATA[ 服务别名分组信息  ]]></xsd:documentation>
67                        </xsd:annotation>
68                    </xsd:attribute>
69                </xsd:extension>
70            </xsd:complexContent>
71        </xsd:complexType>
72    </xsd:element>
73</xsd:schema>

spring.handlers

1http\://rpc.itstack.org/schema/rpc=org.itstack.demo.rpc.config.spring.MyNamespaceHandler

spring.schemas

1http\://rpc.itstack.org/schema/rpc/rpc.xsd=META-INF/rpc.xsd

测试部分

itstack-rpc-consumer.xml

1<?xml version="1.0" encoding="UTF-8"?>
 2<beans xmlns="http://www.springframework.org/schema/beans"
 3       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:rpc="http://rpc.itstack.org/schema/rpc"
 4       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
 5      http://rpc.itstack.org/schema/rpc http://rpc.itstack.org/schema/rpc/rpc.xsd">
 6
 7    <!-- redis配置，保存链接 -->
 8    <rpc:server id="consumer_itstack" host="127.0.0.1" port="6379"/>
 9
10    <rpc:consumer id="consumer_helloService" nozzle="org.itstack.demo.test.service.HelloService" alias="itStackRpc"/>
11
12</beans>

itstack-rpc-provider.xml

1<?xml version="1.0" encoding="UTF-8"?>
 2<beans xmlns="http://www.springframework.org/schema/beans"
 3       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:rpc="http://rpc.itstack.org/schema/rpc"
 4       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
 5      http://rpc.itstack.org/schema/rpc http://rpc.itstack.org/schema/rpc/rpc.xsd">
 6
 7    <rpc:provider id="provider_helloService" nozzle="org.itstack.demo.test.service.HelloService"
 8                 ref="helloService" alias="itStackRpc" />
 9
10</beans>

ApiTest.java

1package org.itstack.demo.test;
 2
 3import org.springframework.context.support.ClassPathXmlApplicationContext;
 4
 5/**
 6 * http://www.itstack.org
 7 * create by fuzhengwei on 2019/5/4
 8 * 本章节主要介绍如何读取自定义配置xml文件字段信息
 9 */
10public class ApiTest {
11
12    public static void main(String[] args) {
13        String[] configs = {"itstack-rpc-consumer.xml", "itstack-rpc-provider.xml"};
14        new ClassPathXmlApplicationContext(configs);
15    }
16
17}

测试结果

12019-05-07 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
22019-05-07 19:44:24,872 main  INFO [org.springframework.beans.factory.xml.XmlBeanDefinitionReader:loadBeanDefinitions:315] - Loading XML bean definitions from class path resource [itstack-rpc-consumer.xml]
32019-05-07 19:44:24,972 main  INFO [org.springframework.beans.factory.xml.XmlBeanDefinitionReader:loadBeanDefinitions:315] - Loading XML bean definitions from class path resource [itstack-rpc-provider.xml]
42019-05-07 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
5服务端信息=> [注册中心地址：127.0.0.1] [注册中心端口：6379] 
6生产者信息=> [接口：org.itstack.demo.test.service.HelloService] [映射：helloService] [别名：itStackRpc]

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