Dubbo

Dubbo是一个高性能、轻量级的开源Java RPC框架，Dubbo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。

RPC（Remote Procedure Call，远程过程调用）是一种基于消息传递的通信协议，允许一台计算机（客户端）调用另一台计算机（服务器）上的程序或方法，就像调用本地方法一样。

在一个项目下，新建三个目录，分别是consumer、interface和provider。
在父pom下添加

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.1.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.xxx</groupId>
    <artifactId>dubbo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>pom</packaging>
    <name>dubbo</name>
    <description>dubbo</description>
    <properties>
        <java.version>17</java.version>
        <dubbo.version>3.2.10</dubbo.version>
        <spring-boot.version>3.1.5</spring-boot.version>
    </properties>
    <repositories>
        <repository>
            <id>aliyun</id>
            <url>https://maven.aliyun.com/repository/public</url>
        </repository>
    </repositories>

    <modules>
        <module>provider</module>
        <module>consumer</module>
        <module>interface</module>
    </modules>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <dependency>
                <groupId>org.apache.dubbo</groupId>
                <artifactId>dubbo-bom</artifactId>
                <version>${dubbo.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
        </dependency>
    </dependencies>

    <build>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <version>${spring-boot.version}</version>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>
</project>

interface

pom

    <parent>
        <groupId>com.xxx</groupId>
        <artifactId>dubbo</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath> <!-- lookup parent from repository -->
    </parent>
    <artifactId>interface</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>interface</name>
    <description>interface</description>

代码

public interface OrderRpcService {
    void hello();
}

provider

pom

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.xxx</groupId>
        <artifactId>dubbo</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath> <!-- lookup parent from repository -->
    </parent>
    <artifactId>provider</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>provider</name>
    <description>provider</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>com.xxx</groupId>
            <artifactId>interface</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

        <!-- dubbo -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-zookeeper-curator5-spring-boot-starter</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

代码

@SpringBootApplication
@EnableDubbo
public class ProviderApplication {

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

}

实现interface中的方法

@DubboService
public class OrderServiceImpl implements OrderRpcService {
    @Override
    public void hello() {
        System.out.println("hello");
    }
}

application.yml

demo:
  orderservice:
    version: 0.0.1

dubbo:
  application:
    name: dubbo-springboot-demo-provider
  registry:
    address: zookeeper://127.0.0.1:2181
  protocol:
    port: -1

consumer

pom

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.xxx</groupId>
        <artifactId>dubbo</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath> <!-- lookup parent from repository -->
    </parent>
    <artifactId>consumer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>consumer</name>
    <description>consumer</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>com.xxx</groupId>
            <artifactId>interface</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

        <!-- dubbo -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-zookeeper-curator5-spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

代码

@SpringBootApplication
@EnableDubbo
public class ConsumerApplication {

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

}

提供一个controller进行测试

@RestController
public class OrderController {
    OrderService orderService;

    @Autowired
    public OrderController(OrderService orderService) {
        this.orderService = orderService;
    }

    @GetMapping("/hello")
    public void hello() {
        orderService.hello();
    }
}

实现service

@Service
public class OrderService {
    @DubboReference
    private OrderRpcService orderRpcService;

    public void hello() {
        // 这里直接调用`interface`中的方法即可
        orderRpcService.hello();
    }
}

application.yml

order:
  orderconsumer:
    version: 0.0.1

dubbo:
  registry:
    address: zookeeper://127.0.0.1:2181
  application:
    qos-port: 33333
    name: dubbo-springboot-demo-provider

运行代码

使用Docker启动一个zookeeper

docker run -d -p 2181:2181 zookeeper

-d 标志告诉 Docker 在后台运行容器，这样就可以继续使用终端而不会被容器进程阻塞。

运行命令mvn package，会打包三个子模块，jar包在target目录下。
在多个命令行工具中运行多个服务提供者和一个消费者，
命令为：java -jar xxx-0.0.1-SNAPSHOT.jar，
访问http://localhost:8080/hello可以看到多个服务者都有打印出hello，因此起到了负载均衡的作用。