SpringBoot+Mybatis多模块（module）项目搭建
SpringBoot+Mybatis多模块（module）项目搭建
开发工具及环境搭建
- IDE: IntelliJ IDEA 2020.1
- JDK: jdk1.8
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
搭建步骤
创建父工程
① IDEA 工具栏选择菜单File ->New ->Project
②选择Spring Initializr，start service URL默认选择Default，点击Next
③填写输入框，点击Next
④这步不需要选择直接点Next
⑤点击Finish创建项目
⑥最终得到的项目目录结构如下
⑦删除无用的.mvn目录、src目录、mvnw、mvnw.cmd文件，最终只留.gitignore和pom.xml文件(图中src目录删掉，我截图的时候忘了…)
创建子模块
①选择项目根目录demo右键呼出菜单，选择New -> Module
②选择Maven，点击Next
③填写ArifactId，点击Finish
④同理添加【demo-dao】、【demo-web】子模块，最终得到项目目录结构如下图
运行项目
①在【demo-web】模块创建com.example.demo.web包，并添加入口类 DemoWebApplication.java
package com.example.demo.web;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DemoWebApplication {
public static void main(String[] args) {
SpringApplication.run(DemoWebApplication.class,args);
}
}
②在父工程【demo】的pom.xml文件中的dependency依赖
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
③在com.example.demo.web包中添加controller目录，并创建一个Controller，添加test方法测试接口是否可以正常访问
package com.example.demo.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 Spring Boot";
}
}
④在【demo-web】子模块的resource目录下创建SpringBoot配置文件application.yml文件，在配置文件中可以修改服务器端口号（默认端口为8080）
server:
port: 9999
⑤运行WebDemoWebApplication类中的main方法启动项目，访问http://localhost:9999/demo/test得到如下效果（如果配置文件没有设置端口号，则访问http://localhost:8080/demo/test）
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父工程pom.xml文件中声明所有子模块依赖
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.examplegroupId>
<artifactId>demo-bizartifactId>
<version>${project.version}version>
dependency>
<dependency>
<groupId>com.examplegroupId>
<artifactId>demo-daoartifactId>
<version>${project.version}version>
dependency>
<dependency>
<groupId>com.examplegroupId>
<artifactId>demo-webartifactId>
<version>${project.version}version>
dependency>
dependencies>
dependencyManagement>
②在【demo-web】模块中的pom.xml文件中添加demo-biz依赖
<dependencies>
<dependency>
<groupId>com.examplegroupId>
<artifactId>demo-bizartifactId>
dependency>
dependencies>
③在【demo-biz】模块中的pom.xml文件中添加demo-dao依赖
<dependencies>
<dependency>
<groupId>com.examplegroupId>
<artifactId>demo-daoartifactId>
dependency>
dependencies>
web层调用biz层的接口测试
①在【demo-biz】层创建com.example.demo包，添加service目录并创建DemoService接口及其实现类
package com.example.demo.service;
public interface DemoService {
String test();
}
package com.example.demo.service.impl;
import com.example.demo.service.DemoService;
import org.springframework.stereotype.Service;
@Service
public class DemoServiceImpl implements DemoService {
@Override
public String test() {
return "Service Test";
}
}
②DemoController通过@Autowired注解注入DemoService，修改DemoController的test方法使之调用DemoService的test方法，最终如下图所示
package com.example.demo.web.controller;
import com.example.demo.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在DemoWebApplication启动类中增加包扫描，设置@SpringBootApplication注解中的scanBasePackages 的值为 com.example.demo，如下图所示
package com.example.demo.web;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication(scanBasePackages = "com.example.demo")
public class DemoWebApplication {
public static void main(String[] args) {
SpringApplication.run(DemoWebApplication.class,args);
}
}
④重新运行DemoWebApplication启动类中的main方法，发现如下报错信息，
将父工程pom.xml文件中的如下代码删除或注释
⑤重新运行main方法，项目正常启动，访问http://localhost:9999/demo/test得到如下效果
集成Mybatis
①父工程pom.xml文件中声明mybatis-spring-boot-starter及lombok依赖
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.mybatis.spring.bootgroupId>
<artifactId>mybatis-spring-boot-starterartifactId>
<version>2.1.2version>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.18.0version>
dependency>
dependencies>
dependencyManagement>
②在【demo-dao】层中的pom.xml文件中添加如下依赖
<dependencies>
<dependency>
<groupId>org.mybatis.spring.bootgroupId>
<artifactId>mybatis-spring-boot-starterartifactId>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>5.1.21version>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
dependency>
dependencies>
③在【demo-dao】层创建com.example.demo.dao包，通过mybatis-genertaor工具生成dao层相关文件（entity，mapper、xml）
④在【demo-dao】层的resource目录下创建SpringBoot配置文件application-dao.yml，并添加jdbc及mybatis相应配置项
spring:
datasource:
username: root
password: root
url: jdbc:mysql:///lexian
driver-class-name: com.mysql.jdbc.Driver
profiles: dao
mybatis:
mapper-locations: classpath:mapping/*.xml
⑤修改【demo-web】层中application.yml配置文件来引用dao层配置文件
#application.yml配置文件中添加profiles配置
spring:
profiles:
active: dao
⑥DemoService通过@Autowired注解注入UserMapper，修改DemoService的test方法使之调用UserMapper的selectByPrimaryKey方法
package com.example.demo.service.impl;
import com.example.demo.dao.entity.User;
import com.example.demo.dao.mapper.UserMapper;
import com.example.demo.service.DemoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class DemoServiceImpl implements DemoService {
@Autowired
private UserMapper userMapper;
@Override
public Object test() {
User user = userMapper.selectByPrimaryKey("1");
return user;
}
}
⑦在【demo-web】层中DemoWebApplication启动类中增加dao层包扫描，添加@MapperScan注解，并设置
basePackages 的值为com.example.demo.mapper，由于需要扫描dao层类，所以web层需要依赖【demo-dao】层，
package com.example.demo.web;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication(scanBasePackages = "com.example.demo")
@MapperScan(basePackages = "com.example.demo.mapper")
public class DemoWebApplication {
public static void main(String[] args) {
SpringApplication.run(DemoWebApplication.class,args);
}
}
⑧重新运行main方法，项目正常启动，访问http://localhost:9999/demo/test得到如下效果
遇到的问题
①项目启动后，出现如下报错，是因为项目中内部集成了mysql-connection-java ：8.×.×以上的版本
Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
在父工程中修改mysql-connection-java版本为5.1.××，项目启动成功