How to Build a Multi‑module Spring Boot + MyBatis Project in IntelliJ IDEA

In this article the author records the process of building a Spring Boot + MyBatis multi‑module project in IntelliJ IDEA, targeting a typical enterprise backend architecture.

Tools and environment : IntelliJ IDEA 2018.2 on macOS.

Project structure : three layers – biz (business), dao (persistence) and web (controller).

Step 1 – Create parent project : Use IDEA → File → New → Project, select Spring Initializr, configure and finish. The resulting directory tree is shown in the screenshots.

Step 2 – Add sub‑modules : Right‑click the parent, New → Module, choose Maven, set artifactId (beta‑biz, beta‑dao, beta‑web) and finish.

Step 3 – Write a simple controller in com.yibao.beta.web :

package com.yibao.beta.web;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication(scanBasePackages = "com.yibao.beta")
@RestController
@RequestMapping("demo")
public class BetaWebApplication {
    public static void main(String[] args) {
        SpringApplication.run(BetaWebApplication.class, args);
    }

    @GetMapping("test")
    public String test() {
        return "Hello World!";
    }
}

Running the application yields http://localhost:8080/demo/test with “Hello World!”.

Step 4 – Configure inter‑module dependencies in the parent pom.xml using <dependencyManagement> and add the appropriate <dependency> entries in each sub‑module.

Step 5 – Integrate MyBatis : add mybatis-spring-boot-starter and lombok to the parent pom, configure application.properties with datasource and MyBatis settings, generate DAO classes with MyBatis Generator, and inject UserMapper into the service layer.

Sample service implementation:

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();
    }
}

After adding @MapperScan("com.yibao.beta.dao.mapper") to the main class, the application starts successfully and the endpoint returns the user record.

Conclusion : The tutorial demonstrates a clean multi‑module backend layout that facilitates maintenance and future micro‑service migration, and mentions possible extensions such as common, server, logback, disconf, Redis, Dubbo, etc.