一.基于idea用springboot搭建多模块项目

1.创建多模块项目，选择spring Initializr 构建sringboot的父类模块

设置好Group，Artifact候直接下一步创建项目

删除多余的文件使springboot-parent父项目只用于管理各个子模块所需jar包的版本

2.子模块的创建

项目右击新建子模块

子模块用maven方式创建

用上面的方式创建多个模块，最后结构如图

3.各模块pom.xml的依赖包和各子模块依赖关系

springboot-parent的pom.xml文件，主要用来管理包依赖版本，不需要导入spring-boot-maven-plugin组件

<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>
    <packaging>pom</packaging>
    <modules>
        <module>springboot-web</module>
        <module>springboot-service</module>
        <module>springboot-dao</module>
    </modules>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example.test</groupId>
    <artifactId>sringboot-parent</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>sringboot-parent</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
        <mybatis.version>2.1.1</mybatis.version>
        <fastjson.version>1.2.1</fastjson.version>
        <druid.version>1.1.10</druid.version>
        <lombok.version>1.16.8</lombok.version>
    </properties>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>${mybatis.version}</version>
            </dependency>
            <!--json alibaba-->
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastjson</artifactId>
                <version>${fastjson.version}</version>
            </dependency>
            <!--druid连接池-->
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid-spring-boot-starter</artifactId>
                <version>${druid.version}</version>
            </dependency>
            <!-- lombok -->
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

springboot-web的pom.xml文件，web模块依赖于service模块，需要spring-boot-maven-plugin组件

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>sringboot-parent</artifactId>
        <groupId>com.example.test</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>springboot-web</artifactId>
    <dependencies>
      <!--引入service模块-->
        <dependency>
            <groupId>${project.groupId}</groupId>
            <artifactId>springboot-service</artifactId>
            <version>${project.version}</version>
        </dependency>
        <!--web的启动器-->
        <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>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <!-- 指定该Main Class为全局的唯一入口 -->
                    <mainClass>com.example.test.SpringbootApplication</mainClass>
                    <layout>ZIP</layout>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal><!--可以把依赖的包都打包到生成的Jar包中-->
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

springboot-service的pom.xml文件，service模块依赖于dao模块

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>sringboot-parent</artifactId>
        <groupId>com.example.test</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springboot-service</artifactId>

    <dependencies>
      <!--引入dao模块-->
        <dependency>
            <groupId>${project.groupId}</groupId>
            <artifactId>springboot-dao</artifactId>
            <version>${project.version}</version>
        </dependency>
        <!--aop启动器-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <!--json alibaba-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>
    </dependencies>
</project>

springboot-dao的pom.xml文件

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>sringboot-parent</artifactId>
        <groupId>com.example.test</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springboot-dao</artifactId>

    <dependencies>
        <!-- mybatis 依赖-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <!--JDBC使用HikariCP连接池 启动器-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <!--druid启动器-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
        </dependency>
        <!--热部署-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
        <!-- lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>
</project>

二.配置必要的文件

在web模块，加入springboot应用启动文件

创建如图文件

application.properties需要引入mybatis的配置

#######数据库配置###########
#数据库驱动
spring.datasource.druid.driver-class-name=com.mysql.jdbc.Driver
#数据库连接url
spring.datasource.druid.url=jdbc:mysql://localhost:3306/test?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf-8
#数据库账号
spring.datasource.druid.username=
spring.datasource.druid.password=
#初始化大小，最小空闲，最大链接
spring.datasource.druid.initial-size=5
spring.datasource.druid.min-idle=5
spring.datasource.druid.max-active=20
#获取连接等待的超时时间 毫秒
spring.datasource.druid.max-wait=60000
#检测需要关闭的空闲连接的间隔时间 毫秒
spring.datasource.druid.time-between-eviction-runs-millis=300000
#设置空闲时是否检测连接可用性
spring.datasource.druid.test-while-idle=true
#获取连接时是否检测连接可用性
spring.datasource.druid.test-on-borrow=false
spring.datasource.druid.test-on-return=false

###########Mybatis配置#############
#mybatis的mapper文件位置
mybatis.mapper-locations=classpath:mapper/*.xml

三.项目打包

1.需要把依赖的子模块install

点击springboot-parent的install把所有模块变成jar存入maven版本库中

点击springboot-web的package打包项目

2.把打包好在项目target下生产的springboot-web-0.0.1-SNAPSHOT.jar复制出来，按
java -jar springboot-web-0.0.1-SNAPSHOT.jar启动项目即可

启动项目