nacos(六): 创建第一个多模块微服务项目(生产者与消费者)

要创建出生产者与消费者一体的多模块项目，总体来说分成三个步骤。分别是先创建出项目主体，再分别创建出生产者与消费者。

步骤一：创建项目主体

1. 先创建一个单体项目作为项目的主题。在这里，我们不用脚手架，通过IDEA的向导直接进行创建。根据下图进行新建项目的配置：

2. 然后点击下一击，选择版本与依赖项：

3. 在生成的主项目中，只保留pom.xml，其余的文件可以全部删掉：

4. 将pom.xml的内容进行如下修改：

<?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>
    <modules>
        <module>producer</module>
        <module>consumer</module>
    </modules>

    <groupId>com.example</groupId>
    <artifactId>alibabanacos</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>alibabanacos</name>
    <description>alibabanacos</description>

    <packaging>pom</packaging>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.7.6</spring-boot.version>
        <spring-cloud-alibaba.version>2021.0.5.0</spring-cloud-alibaba.version>
    </properties>
    <dependencies>
        <!--springboot-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

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

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

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>

        </plugins>
    </build>

</project>

其中，有几个配置节需要注意：

<modules>配置节代表着后面要创建的子模块的名称；

<packaging>配置节代表打包方式，因为主项目只有一个pom.xml，主要是协调和管理子项目，所以无需打包改为pom即可。

步骤二：创建生产者producer

1. 在主项目下新建producer模块：

2. 在main包下面创建出resources文件夹：

3. 在producer下创建target文件夹：

4. 之后如下修改pom.xml

<?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.example</groupId>
        <artifactId>alibabanacos</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <packaging>jar</packaging>
    <artifactId>producer</artifactId>
    <description>producer</description>
    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.7.6</spring-boot.version>
    </properties>
    <dependencies>
        <!--springboot-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

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

        <!-- 服务发现(生产者)  -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>${spring-boot.version}</version>
                <configuration>
                    <mainClass>com.example.producer.ProducerApplication</mainClass>
                    <skip>false</skip>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

5. 在启动类上添加@EnableDiscoveryClient注解

6.  在resources资源目录下添加application.yml文件

并在文件中添加如下配置：

server:
  port: 8085

spring:
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848
        username: nacos
        password: nacos
      config:
        server-addr: 127.0.0.1:8848
        username: nacos
        password: nacos
        namespace: public

    loadbalancer:
      nacos:
        enabled: true

  application:
    name: product

到这里对生产者的配置已经完成，这时启动生产者，即可在nacos后台的服务列表中看到product实例：

步骤三：创建消费者consumer

总体步骤和生产者创建几乎一致，不同的地方在于以下几个方面：

1. pom.xml

<?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.example</groupId>
        <artifactId>alibabanacos</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <artifactId>consumer</artifactId>
    <packaging>jar</packaging>

    <dependencies>
        <!--springboot-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

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

        <!-- 服务发现(生产者)  -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>

        <!--消费者-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-loadbalancer</artifactId>
            <version>3.1.5</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>${spring-boot.version}</version>
                <configuration>
                    <mainClass>com.example.consumer.ConsumerApplication</mainClass>
                    <skip>false</skip>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

2. application.yml

server:
  port: 8086

spring:
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848
        username: nacos
        password: nacos
      config:
        server-addr: 127.0.0.1:8848
        file-extension: properties
        username: nacos
        password: nacos
    loadbalancer:
      nacos:
        enabled: true

  application:
    name: consumer

具体消费者如何通过loadbalance调用生产者提供的服务，可以参考《nacos(四): 创建第一个消费者Conumer(单体)》。

最终成果：整个项目的工程目录结构基本如下

本文到这里就完成了。下一篇，我们将一起关注网关gateway的使用: ）