基于Protobuf协议的Dubbo与SpringBoot的结合

工程概况父pomdubbo-provider

通过proto3定义服务打包发布服务dubbo-provider-service实现服务dubbo-provider-web提供服务 dubbo-consumer

dubbo-consumer-apidubbo-consumer-servicedubbo-consumer-web提供服务
这里使用Protobuf作为IDL 定义Dubbo服务，并于SpringBoot相结合，搭建最原始的服务提供及消费模型。基于dubbo2.7.13，注册中心使用zookeeper。

dubbo-provider$ tree -L 1 .
.
├── dubbo-provider-api
├── dubbo-provider-service
├── dubbo-provider-web
└── pom.xml

dubbo-consumer$ tree -L 1 .
.
├── dubbo-consumer-api
├── dubbo-consumer-service
├── dubbo-consumer-web
└── pom.xml

这里新建了两个SpringBoot项目，dubbo-provider用于提供对外服务，其中 dubbo-provider-api 用于提供api，会将其独立打包发布，用于第三方调用（如dubbo-consumer）。dubbo-consumer会远程调用dubbo-provider提供的服务。
两个项目中分别有3个子项组成，api仅仅用于定义对外提供服务接口（服务内部的接口不在此定义），service依赖api的接口，并给予具体的实现，而web则负责调用实现，对外提供服务。

先给出工程根目录下pom文件的内容，这个父pom文件主要用于统一管理一些包的依赖

    4.0.0
    com.demo.dubbo.provider
    dubbo-provider
    1.0-SNAPSHOT
    pom

    
        UTF-8
        UTF-8
        2.7.13
        1.40.1
        0.0.2
        3.7.0
    

    
        ...
    
    
        

            
                org.apache.dubbo
                dubbo-spring-boot-starter
                ${dubbo.version}
            
        
            
                org.apache.dubbo
                dubbo-dependencies-zookeeper
                ${dubbo.version}
            
            
                org.apache.dubbo
                dubbo-serialization-protobuf
                ${dubbo.version}
            

        
    
    
        
            ...
        
    
    
        
            ...
        
    
    
        
            ...
        
    
    
        dubbo-provider-api
        dubbo-provider-service
        dubbo-provider-web
    

dubbo-provider-api的结构如下，注意这里的service目录下的文件都是根据proto协议自动生成的，请不要修改它。

dubbo-provider/dubbo-provider-api$ ll
总用量 20
drwxrwxr-x  4 mi mi 4096 1月  14 16:34 ./
drwxrwxr-x 13 mi mi 4096 1月  13 09:32 ../
-rw-rw-r--  1 mi mi 2802 1月  14 16:34 pom.xml
drwxrwxr-x  3 mi mi 4096 1月  11 17:49 src/
drwxrwxr-x  8 mi mi 4096 1月  14 16:35 target/
dubbo-provider/dubbo-provider-api$ tree .
.
├── pom.xml
├── src
│ └── main
│     ├── java
│     │ └── com
│     │     └── demo
│     │         └── dubbo
│     │             └── provider
│     │                 └── api
│     │                     └── service
│     │                         ├── DemoServiceDubbo.java
│     │                         ├── DemoService.java
│     │                         ├── DemoServiceProto.java
│     │                         ├── HelloReply.java
│     │                         ├── HelloReplyOrBuilder.java
│     │                         ├── HelloRequest.java
│     │                         └── HelloRequestOrBuilder.java
│     │                        
│     └── proto
│         └── DemoService.proto
└── target...

DemoService.proto定义如下：

syntax = "proto3";

option java_multiple_files = true;
option java_package = "com.demo.dubbo.provider.api.service";
option java_outer_classname = "DemoServiceProto";
option objc_class_prefix = "DEMOSRV";

package demoservice;

// The demo service definition.
service DemoService {
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

这里通过message关键字定义了请求和响应的内容格式，通过service关键字定义服务的接口。

借助 protobuf-maven-plugin 编译proto文件，并将生成的文件放到源码目录下，便于之后可以将dubbo-provider-api进行打包发布。

	4.0.0
	
		com.demo.dubbo.provider
		dubbo-provider
		1.0-SNAPSHOT
	
	dubbo-provider-api

	
		
			org.apache.dubbo
			dubbo-serialization-protobuf
		
	

	
		
			
				kr.motd.maven
				os-maven-plugin
				1.6.1
			
		
		
			
				org.xolstice.maven.plugins
				protobuf-maven-plugin
				0.5.1
				
					com.google.protobuf:protoc:3.7.1:exe:${os.detected.classifier}
					src/main/java
					false
					
						
							dubbo
							org.apache.dubbo
							dubbo-compiler
							${dubbo.compiler.version}
							org.apache.dubbo.gen.dubbo.Dubbo3Generator
						
					
				
				
					
						
							compile
							test-compile
						
					
				
			
			
				org.codehaus.mojo
				build-helper-maven-plugin
				
					
						generate-sources
						
							add-source
						
						
							
								src/main/java
							
						
					
				
			
			
				org.apache.maven.plugins
				maven-compiler-plugin
				${maven-compiler-plugin.version}
				
					1.8
					1.8
				
			
		
	

dubbo-provider-service将实现dubbo-provider-api中的接口。

    4.0.0
    
        com.demo.dubbo.provider
        dubbo-provider
        1.0-SNAPSHOT
    
    dubbo-provider-service
    
        
            com.demo.dubbo.provider
            dubbo-provider-api
        
    

package com.demo.dubbo.provider.service;

import com.demo.dubbo.provider.api.service.DemoService;
import com.demo.dubbo.provider.api.service.HelloReply;
import com.demo.dubbo.provider.api.service.HelloRequest;
import org.apache.dubbo.config.annotation.DubboService;
import org.apache.dubbo.rpc.RpcContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import java.util.concurrent.CompletableFuture;

@DubboService
@Component
public class DemoServiceImpl implements DemoService {
    private static final Logger logger = LoggerFactory.getLogger(DemoServiceImpl.class);

    @Override
    public HelloReply sayHello(HelloRequest request) {
        logger.info("Hello " + request.getName() + ", request from consumer: " + RpcContext.getContext().getRemoteAddress());
        HelloReply response = HelloReply.newBuilder()
                .setMessage("Hello " + request.getName() + ", response from provider: "
                        + RpcContext.getContext().getLocalAddress())
                .build();
        logger.info("response:{}", response);
        return response;
    }

    @Override
    public CompletableFuture sayHelloAsync(HelloRequest request) {
        return CompletableFuture.completedFuture(sayHello(request));
    }
}

pom.xml

	4.0.0
	
		com.demo.dubbo.provider
		dubbo-provider
		1.0-SNAPSHOT
	
	dubbo-provider-web
	jar
	dubbo-provider-web
	dubbo-provider-web project for Spring Boot

	
		2.4.0
		1.8
	

	
		
			org.springframework.boot
			spring-boot-starter-web
			${springboot.version}
		

		
			org.apache.dubbo
			dubbo-spring-boot-starter
		

		
			org.apache.dubbo
			dubbo-dependencies-zookeeper
			2.7.13
			pom
		

		
			com.demo.dubbo.provider
			dubbo-provider-service
			1.0-SNAPSHOT
		

	
	
		dubbo-provider-web
		
			
				src/main/resources
				true
				
					**/application.properties
					**/logback.xml
				
			
		
		
			
				org.springframework.boot
				spring-boot-maven-plugin
				${springboot.version}
				
					
						
							repackage
						
					
				
			
		
	

application.properties

dubbo.application.name=dubbo-provider-provider
dubbo.registry.address=zookeeper://127.0.0.1:2181
dubbo.protocol.name=dubbo
dubbo.protocol.serialization=protobuf

注意：dubbo.protocol.serialization=protobuf一定要添加，否则会用dubbo默认的序列化协议（Hessian2），将导致序列化失败，无法将参数写入请求体中。

通过EnableDubbo实现自动装配dubbo的配置

package com.demo.dubbo.provider.web;

import org.apache.dubbo.config.spring.context.annotation.EnableDubbo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication(scanbasePackages = "com.demo.dubbo.provider")
@EnableDubbo(scanbasePackages = "com.demo.dubbo.provider")
public class ProviderBootWebApplication {

	public static void main(String[] args) {
		SpringApplication.run(ProviderBootWebApplication.class, args);
	}
}

dubbo-consumer-api这里无需定义，因为我们不打算对外提供服务。

dubbo-consumer-service将依赖dubbo-provider-api，以便直接使用其中服务定义。

    4.0.0
    
        com.demo.dubbo.consumer
        dubbo-consumer
        1.0-SNAPSHOT
    
    dubbo-consumer-service

    
        
        
            com.demo.dubbo.provider
            dubbo-provider-api
            1.0-SNAPSHOT
        

        
            org.apache.dubbo
            dubbo-common
            2.7.13
            compile
        
    

package com.demo.dubbo.consumer.service;

import com.demo.dubbo.provider.api.service.DemoService;
import com.demo.dubbo.provider.api.service.HelloReply;
import com.demo.dubbo.provider.api.service.HelloRequest;
import lombok.extern.slf4j.Slf4j;
import org.apache.dubbo.config.annotation.DubboReference;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Slf4j
@Service
public class ConsumerService {

    @DubboReference(version = "*", loadbalance = "random")
    private DemoService demoService;

    public String hello(String name) {
        log.info("receiver:{}", name);
        HelloRequest request = HelloRequest.newBuilder().setName(name).build();
        HelloReply response = demoService.sayHello(request);
        log.info("response:{}", response);

        return response.getMessage();
    }
}

通过DubboReference引用dubbo-provider-api提供的服务。关于DubboReference注解的详细内容，在此不展开详述。在此,version用于版本控制：当一个接口实现，出现不兼容升级时，可以用版本号过渡，版本号不同的服务相互间不引用。loadbalance用于负载均衡，常见的算法有random,roundRobin,leastActive,consistentHash。

pom文件参考 dubbo-provider-web.
application.properties

dubbo.application.name=dubbo-consumer
dubbo.registry.address=zookeeper://127.0.0.1:2181
dubbo.protocol.name=dubbo
dubbo.protocol.serialization=protobuf

注意：dubbo.protocol.serialization=protobuf一定要添加，否则会用dubbo默认的序列化协议，将导致序列化失败，无法将请求参数序列化成功。

package com.demo.dubbo.consumer.web;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication(scanbasePackages = "com.demo.dubbo")
public class ConsumerBootWebApplication {

	public static void main(String[] args) {
		SpringApplication.run(ConsumerBootWebApplication.class, args);
	}
}