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springboot 多模块将dao(mybatis)项目拆分出去

作者：Sniper_ZL

这篇文章主要介绍了springboot 多模块将dao(mybatis)项目拆分出去，小编觉得挺不错的，现在分享给大家，也给大家做个参考。一起跟随小编过来看看吧

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

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

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

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

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

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

@Service
public 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.

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: 8080

mybatis:
 config-location: /mapper/*.xml

spring:
 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"})
@SpringBootApplication
public 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:

@Configuration
public 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:

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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