springboot 多模块将dao(mybatis)项目拆分出去

2024-07-14 08:40:36

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前言:

以前我们在建项目的时候, 要么将所有的package建在一个项目里面, 在处理引用的时候, 真的很方便. 不用担心, 有些东西配置不到或者读取不到.

或者, 将package独立出去, 到一个项目中或者子项目中. 这时候, 项目中的引用处理, 还是有些麻烦的. 不过好处更多, 不再表述.

在 idea 里面, 推荐使用多模块建项目, 而不再是 eclipse 里面的那种方式. 那这里, 就试着将一个springboot 的项目拆分到子模块中去, 看看效果如何.

项目拆分:

1. 目录变化

springboot,多模块项目拆分,多模块,拆分,mybatis

2. 父项目

父pom.xml理论上来说, 应该是对子项目中的引用进行一个约束, 主要是版本约束.

所以父 pom.xm 中, 应该使用dependencyManagement 来约束子项目中 jar 包版本.

然后对于一些子项目都用得着的引用, 可以提到父项目中去.

<?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">  <modelVersion>4.0.0</modelVersion>  <groupId>cn.elvinle</groupId>  <artifactId>parent</artifactId>  <version>0.0.1-SNAPSHOT</version>  <packaging>pom</packaging>  <name>parent</name>  <description>Demo project for Spring Boot</description>  <parent>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-starter-parent</artifactId>    <version>1.5.9.RELEASE</version>    <relativePath/> <!-- lookup parent from repository -->  </parent>  <modules>    <module>pojo</module>    <module>web</module>    <module>dao</module>    <module>service</module>    <module>simpl</module>  </modules>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>    <java.version>1.8</java.version>    <druid.version>1.1.3</druid.version>    <mybatis.boot.starter.version>1.3.1</mybatis.boot.starter.version>    <mysql.connector.java.version>5.1.44</mysql.connector.java.version>  </properties>  <dependencyManagement>    <dependencies>      <dependency>        <groupId>com.alibaba</groupId>        <artifactId>druid</artifactId>        <version>${druid.version}</version>      </dependency>      <dependency>        <groupId>org.mybatis.spring.boot</groupId>        <artifactId>mybatis-spring-boot-starter</artifactId>        <version>${mybatis.boot.starter.version}</version>      </dependency>      <dependency>        <groupId>mysql</groupId>        <artifactId>mysql-connector-java</artifactId>        <version>${mysql.connector.java.version}</version>      </dependency>    </dependencies>  </dependencyManagement>  <!--申明依赖关系-->  <dependencies>    <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>    </dependency>  </dependencies>  <build>    <plugins>      <plugin>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-maven-plugin</artifactId>      </plugin>    </plugins>  </build></project>

3. 子项目 - pojo

springboot,多模块项目拆分,多模块,拆分,mybatis

3.1 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 http://maven.apache.org/xsd/maven-4.0.0.xsd">  <modelVersion>4.0.0</modelVersion>  <parent>    <groupId>cn.elvinle</groupId>    <artifactId>parent</artifactId>    <version>0.0.1-SNAPSHOT</version>  </parent>  <groupId>cn.elvinle</groupId>  <artifactId>pojo</artifactId>  <version>0.0.1-SNAPSHOT</version>  <packaging>jar</packaging>  <name>pojo</name>  <description>Demo project for Spring Boot</description>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>    <java.version>1.8</java.version>  </properties>  <build>    <plugins>      <plugin>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-maven-plugin</artifactId>      </plugin>    </plugins>  </build></project>

3.2 db实体

package cn.elvinle.pojo;/** * @author: elvin */public class User {  private int id;  private String name;  public int getId() {    return id;  }  public void setId(int id) {    this.id = id;  }  public String getName() {    return name;  }  public void setName(String name) {    this.name = name;  }}

对于pojo和dao中的内容, 可以使用mybatis逆向工程生成, 可以省去很多麻烦.

4. 子项目 - dao

springboot,多模块项目拆分,多模块,拆分,mybatis

4.1 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 http://maven.apache.org/xsd/maven-4.0.0.xsd">  <modelVersion>4.0.0</modelVersion>  <parent>    <groupId>cn.elvinle</groupId>    <artifactId>parent</artifactId>    <version>0.0.1-SNAPSHOT</version>  </parent>  <groupId>cn.elvinle</groupId>  <artifactId>dao</artifactId>  <version>0.0.1-SNAPSHOT</version>  <packaging>jar</packaging>  <name>dao</name>  <description>Demo project for Spring Boot</description>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>    <java.version>1.8</java.version>  </properties>  <dependencies>    <!-- 内部引用 -->    <dependency>      <groupId>cn.elvinle</groupId>      <artifactId>pojo</artifactId>      <version>0.0.1-SNAPSHOT</version>    </dependency>    <!-- 外部引用 -->    <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->    <dependency>      <groupId>com.alibaba</groupId>      <artifactId>druid</artifactId>    </dependency>    <dependency>      <groupId>mysql</groupId>      <artifactId>mysql-connector-java</artifactId>    </dependency>    <dependency>      <groupId>org.mybatis.spring.boot</groupId>      <artifactId>mybatis-spring-boot-starter</artifactId>    </dependency>  </dependencies>  <build>    <plugins>      <plugin>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-maven-plugin</artifactId>      </plugin>    </plugins>  </build></project>

4.2 mapper

UserMapper.java:

public interface UserMapper {  public List<User> getAll();}

UserMapper.xml:

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" ><mapper namespace="cn.elvinle.dao.mapper.UserMapper" >  <select id="getAll" resultType="cn.elvinle.pojo.User">    select * from user  </select></mapper>

5. 子项目 - service

springboot,多模块项目拆分,多模块,拆分,mybatis

5.1 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 http://maven.apache.org/xsd/maven-4.0.0.xsd">  <modelVersion>4.0.0</modelVersion>  <parent>    <groupId>cn.elvinle</groupId>    <artifactId>parent</artifactId>    <version>0.0.1-SNAPSHOT</version>  </parent>  <groupId>cn.elvinle</groupId>  <artifactId>service</artifactId>  <version>0.0.1-SNAPSHOT</version>  <packaging>jar</packaging>  <name>service</name>  <description>Demo project for Spring Boot</description>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>    <java.version>1.8</java.version>  </properties>  <dependencies>    <dependency>      <groupId>cn.elvinle</groupId>      <artifactId>pojo</artifactId>      <version>0.0.1-SNAPSHOT</version>    </dependency>  </dependencies>  <build>    <plugins>      <plugin>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-maven-plugin</artifactId>      </plugin>    </plugins>  </build></project>

5.2 UserService.java

public interface UserService {  public List<User> getAll();}

6. 子项目 - simpl

springboot,多模块项目拆分,多模块,拆分,mybatis

6.1 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 http://maven.apache.org/xsd/maven-4.0.0.xsd">  <modelVersion>4.0.0</modelVersion>  <parent>    <groupId>cn.elvinle</groupId>    <artifactId>parent</artifactId>    <version>0.0.1-SNAPSHOT</version>  </parent>  <groupId>cn.elvinle</groupId>  <artifactId>simpl</artifactId>  <version>0.0.1-SNAPSHOT</version>  <packaging>jar</packaging>  <name>simpl</name>  <description>Demo project for Spring Boot</description>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>    <java.version>1.8</java.version>  </properties>  <dependencies>    <dependency>      <groupId>cn.elvinle</groupId>      <artifactId>pojo</artifactId>      <version>0.0.1-SNAPSHOT</version>    </dependency>    <dependency>      <groupId>cn.elvinle</groupId>      <artifactId>service</artifactId>      <version>0.0.1-SNAPSHOT</version>    </dependency>    <dependency>      <groupId>cn.elvinle</groupId>      <artifactId>dao</artifactId>      <version>0.0.1-SNAPSHOT</version>    </dependency>  </dependencies>  <build>    <plugins>      <plugin>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-maven-plugin</artifactId>      </plugin>    </plugins>  </build></project>

6.2 UserSImpl

@Servicepublic class UserSImpl implements UserService {  @Autowired  private UserMapper userMapper;  @Override  public List<User> getAll() {    System.out.println("UserSImpl getAll");    return userMapper.getAll();  }}

7. 子项目 - web

关键的地方来了.

springboot,多模块项目拆分,多模块,拆分,mybatis

7.1 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 http://maven.apache.org/xsd/maven-4.0.0.xsd">  <modelVersion>4.0.0</modelVersion>  <parent>    <groupId>cn.elvinle</groupId>    <artifactId>parent</artifactId>    <version>0.0.1-SNAPSHOT</version>  </parent>  <groupId>cn.elvinle</groupId>  <artifactId>web</artifactId>  <version>0.0.1-SNAPSHOT</version>  <packaging>jar</packaging>  <name>web</name>  <description>Demo project for Spring Boot</description>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>    <java.version>1.8</java.version>  </properties>  <dependencies>    <dependency>      <groupId>cn.elvinle</groupId>      <artifactId>simpl</artifactId>      <version>0.0.1-SNAPSHOT</version>    </dependency>  </dependencies>  <build>    <plugins>      <plugin>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-maven-plugin</artifactId>      </plugin>    </plugins>  </build></project>

7.2 application.yml

server: context-path: /parent port: 8080mybatis: config-location: /mapper/*.xmlspring: datasource:  username: root  password: root  url: jdbc:mysql://localhost:3306/shop?useUnicode=true&characterEncoding=utf-8  driver-class-name: com.mysql.jdbc.Driver

7.3 控制器

@RestController@RequestMapping("api")public class ApiController {  @Autowired  private UserService userService;  @RequestMapping("index")  public List<User> index(){    List<User> all = userService.getAll();    return all;  }}

到目前为止, 没什么特别的, 都是正常修改, 接下来, 会出现与不分模块不同的地方.

7.4 入口处修改

@ComponentScan({"cn.elvinle"})@SpringBootApplicationpublic class WebApplication {  public static void main(String[] args) {    SpringApplication.run(WebApplication.class, args);  }}

这时候, 如果直接运行起程序, 是不会成功访问的. 原因在于, mybatis的自动化配置和自动化创建, 没有支持到多模块中.

这时候, 需要我们手动进行配置和创建.

7.5 Mybatis java 配置

<!-- mybatis 的工厂 -->  <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">    <property name="dataSource" ref="dataSource" />    <property name="configLocation" value="classpath:mybatis/SqlMapConfig.xml"/>    <!-- 自动扫描mapping.xml文件 -->    <!--<property name="mapperLocations" value="classpath:mapper/*.xml" />-->  </bean>  <!-- DAO接口所在包名，Spring会自动查找其下的类 -->  <bean id="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">    <property name="basePackage" value="cn.elvinle.bookshop.mapper" />    <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>  </bean>

可以对照着上面的配置文件, 进行java配置

MybatisConfig:

@Configurationpublic class MybatisConfig {  @Value("${mybatis.config-location}")  private String mapperLocationPattern;  @Bean  @ConfigurationProperties(prefix = "spring.datasource")  public DataSource dataSource(){return new com.alibaba.druid.pool.DruidDataSource();  }  @Bean(name="sqlSessionFactory")  public SqlSessionFactory sqlSessionFactory() throws Exception{    SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();    sqlSessionFactoryBean.setDataSource(dataSource());    PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();    sqlSessionFactoryBean.setMapperLocations(resolver.getResources(mapperLocationPattern));    return sqlSessionFactoryBean.getObject();  }}

MybatisMapperScannerConfig:

@Configuration@AutoConfigureAfter(MybatisConfig.class)@MapperScan("cn.elvinle.dao.mapper")public class MybatisMapperScannerConfig {  public MapperScannerConfigurer mapperScannerConfigurer(){    MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();    mapperScannerConfigurer.setSqlSessionFactoryBeanName("sqlSessionFactory");    mapperScannerConfigurer.setBasePackage("cn.elvinle.dao.mapper");    return mapperScannerConfigurer;  }}

OK, 到这里, 就可以把程序跑起来了, 看一下结果:

springboot,多模块项目拆分,多模块,拆分,mybatis