SpringBoot+Mybatis多模块（module）项目搭建教程

偏执的太偏执、 2022-09-13 04:12 256阅读 0赞

## 一、前言 ##

最近公司项目准备开始重构，框架选定为SpringBoot+Mybatis，本篇主要记录了在IDEA中搭建SpringBoot多模块项目的过程。

### 1、开发工具及系统环境 ###

*  IDE：IntelliJ IDEA 2018.2
 *  系统环境：mac OSX

### 2、项目目录结构 ###

*  biz层：业务逻辑层
 *  dao层：数据持久层
 *  web层：请求处理层

## 二、搭建步骤 ##

### 1、创建父工程 ###

① IDEA 工具栏选择菜单 File -> New -> Project...

![1cd4f31be7ffb42c659813f063c6343c.png][]

② 选择Spring Initializr，Initializr默认选择Default，点击Next

![48428f2e7289e1c311dabeb22622028b.png][]

③ 填写输入框，点击Next

![5694ad901d11c0ff9d26ed285af1c595.png][]

④ 这步不需要选择直接点Next

![29a3af9102bf0619829b47df7849fd40.png][]

⑤ 点击Finish创建项目

![9d6bcb0e967f91197fd862a6e77b8a44.png][]

⑥ 最终得到的项目目录结构如下

![11f33a86b659e0fa0c79317c287f5d22.png][]

⑦ 删除无用的.mvn目录、src目录、mvnw及mvnw.cmd文件，最终只留.gitignore和pom.xml

![109f6661f814819a3152ad49492f0c73.png][]

### 2、创建子模块 ###

① 选择项目根目录beta右键呼出菜单，选择New -> Module

![1990bf5f2d0184c20719a6088c6e2ce3.png][]

② 选择Maven，点击Next

![533017abad3a82dd098993f8e00a2165.png][]

③ 填写ArifactId，点击Next

![c51a0305cba0a8707f6c4338c0df5d23.png][]

④ 修改Module name增加横杠提升可读性，点击Finish

![af45ad190ba83b11e9fe5e21fbd352e4.png][]

⑤ 同理添加【beta-dao】、【beta-web】子模块，最终得到项目目录结构如下图

![ab8a170c4b7770d74c79a290e71de2e8.png][]

### 3、运行项目 ###

① 在beta-web层创建com.yibao.beta.web包（注意：这是多层目录结构并非单个目录名，com >> yibao >> beta >> web）并添加入口类BetaWebApplication.java

package com.yibao.beta.web;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    
    @SpringBootApplication
    public class BetaWebApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(BetaWebApplication.class, args);
        }
    }

② 在com.yibao.beta.web包中添加controller目录并新建一个controller，添加test方法测试接口是否可以正常访问

package com.yibao.beta.web.controller;
    
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    @RequestMapping("demo")
    public class DemoController {
    
        @GetMapping("test")
        public String test() {
            return "Hello World!";
        }
    }

③ 运行BetaWebApplication类中的main方法启动项目，默认端口为8080，访问http://localhost:8080/demo/test得到如下效果

![ea9f46e8b92b813e224243873e2e4cb9.png][]

以上虽然项目能正常启动，但是模块间的依赖关系却还未添加，下面继续完善

### 4、配置模块间的依赖关系 ###

各个子模块的依赖关系：biz层依赖dao层，web层依赖biz层

① 父pom文件中声明所有子模块依赖（dependencyManagement及dependencies的区别自行查阅文档）

<dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>com.yibao.beta</groupId>
                <artifactId>beta-biz</artifactId>
                <version>${beta.version}</version>
            </dependency>
            <dependency>
                <groupId>com.yibao.beta</groupId>
                <artifactId>beta-dao</artifactId>
                <version>${beta.version}</version>
            </dependency>
            <dependency>
                <groupId>com.yibao.beta</groupId>
                <artifactId>beta-web</artifactId>
                <version>${beta.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

其中$\{beta.version\}定义在properties标签中

② 在beta-web层中的pom文件中添加beta-biz依赖

<dependencies>
        <dependency>
            <groupId>com.yibao.beta</groupId>
            <artifactId>beta-biz</artifactId>
        </dependency>
    </dependencies>

③ 在beta-biz层中的pom文件中添加beta-dao依赖

<dependencies>
        <dependency>
            <groupId>com.yibao.beta</groupId>
            <artifactId>beta-dao</artifactId>
        </dependency>
    </dependencies>

### 5、web层调用biz层接口测试 ###

① 在beta-biz层创建com.yibao.beta.biz包，添加service目录并在其中创建DemoService接口类

package com.yibao.beta.biz.service;
    
    
    public interface DemoService {
    
        String test();
    }

package com.yibao.beta.biz.service.impl;
    
    import com.yibao.beta.biz.service.DemoService;
    import org.springframework.stereotype.Service;
    
    
    @Service
    public class DemoServiceImpl implements DemoService {
    
        @Override
        public String test() {
            return "test";
        }
    }

② DemoController通过@Autowired注解注入DemoService，修改DemoController的test方法使之调用DemoService的test方法，最终如下所示

package com.yibao.beta.web.controller;
    
    import com.yibao.beta.biz.service.DemoService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    
    @RestController
    @RequestMapping("demo")
    public class DemoController {
    
        @Autowired
        private DemoService demoService;
    
        @GetMapping("test")
        public String test() {
            return demoService.test();
        }
    }

③ 再次运行BetaWebApplication类中的main方法启动项目，发现如下报错

***************************
    APPLICATION FAILED TO START
    ***************************
    
    Description:
    
    Field demoService in com.yibao.beta.web.controller.DemoController required a bean of type 'com.yibao.beta.biz.service.DemoService' that could not be found.
    
    
    Action:
    
    Consider defining a bean of type 'com.yibao.beta.biz.service.DemoService' in your configuration.

原因是找不到DemoService类，此时需要在BetaWebApplication入口类中增加包扫描，设置@SpringBootApplication注解中的scanBasePackages值为com.yibao.beta，最终如下所示

package com.yibao.beta.web;
    
    import org.mybatis.spring.annotation.MapperScan;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    
    
    @SpringBootApplication(scanBasePackages = "com.yibao.beta")
    @MapperScan("com.yibao.beta.dao.mapper")
    public class BetaWebApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(BetaWebApplication.class, args);
        }
    }

设置完后重新运行main方法，项目正常启动，访问http://localhost:8080/demo/test得到如下效果

![b2758563559b8c04d877da0a37c68402.png][]

### 6、集成Mybatis ###

① 父pom文件中声明mybatis-spring-boot-starter及lombok依赖

dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.3.2</version>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.16.22</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

② 在beta-dao层中的pom文件中添加上述依赖

<dependencies>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

③ 在beta-dao层创建com.yibao.beta.dao包，通过mybatis-genertaor工具生成dao层相关文件（DO、Mapper、xml），存放目录如下

![c0e0b3407d5e8cb7a7be112a7c12cbc3.png][]

④ applicatio.properties文件添加jdbc及mybatis相应配置项

spring.datasource.driverClassName = com.mysql.jdbc.Driver
    spring.datasource.url = jdbc:mysql://192.168.1.1/test?useUnicode=true&characterEncoding=utf-8
    spring.datasource.username = test
    spring.datasource.password = 123456
    
    mybatis.mapper-locations = classpath:mybatis/*.xml
    mybatis.type-aliases-package = com.yibao.beta.dao.entity

⑤ DemoService通过@Autowired注解注入UserMapper，修改DemoService的test方法使之调用UserMapper的selectByPrimaryKey方法，最终如下所示

package com.yibao.beta.biz.service.impl;
    
    import com.yibao.beta.biz.service.DemoService;
    import com.yibao.beta.dao.entity.UserDO;
    import com.yibao.beta.dao.mapper.UserMapper;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    
    @Service
    public class DemoServiceImpl implements DemoService {
    
        @Autowired
        private UserMapper userMapper;
    
        @Override
        public String test() {
            UserDO user = userMapper.selectByPrimaryKey(1);
            return user.toString();
        }
    }

⑥ 再次运行BetaWebApplication类中的main方法启动项目，发现如下报错

APPLICATION FAILED TO START
    ***************************
    
    Description:
    
    Field userMapper in com.yibao.beta.biz.service.impl.DemoServiceImpl required a bean of type 'com.yibao.beta.dao.mapper.UserMapper' that could not be found.
    
    
    Action:
    
    Consider defining a bean of type 'com.yibao.beta.dao.mapper.UserMapper' in your configuration.

原因是找不到UserMapper类，此时需要在BetaWebApplication入口类中增加dao层包扫描，添加@MapperScan注解并设置其值为com.yibao.beta.dao.mapper，最终如下所示

设置完后重新运行main方法，项目正常启动，访问http://localhost:8080/demo/test得到如下效果

![eb24aaae46b606e67ee52f31ebf7e76c.png][]

至此，一个简单的SpringBoot+Mybatis多模块项目已经搭建完毕，我们也通过启动项目调用接口验证其正确性。

## 四、总结 ##

一个层次分明的多模块工程结构不仅方便维护，而且有利于后续微服务化。在此结构的基础上还可以扩展common层（公共组件）、server层（如dubbo对外提供的服务）

此为项目重构的第一步，后续还会的框架中集成logback、disconf、redis、dubbo等组件

## 五、未提到的坑 ##

在搭建过程中还遇到一个maven私服的问题，原因是公司内部的maven私服配置的中央仓库为阿里的远程仓库，它与maven自带的远程仓库相比有些jar包版本并不全，导致在搭建过程中好几次因为没拉到相应jar包导致项目启动不了。

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> 作者 | 枫本非凡
> 
> 链接 | cnblogs.com/orzlin/p/9717399.html

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