springboot 多模块将dao(mybatis)项目拆分出去

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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