SpringBoot（九）之整合mybatis

SpringBoot（九）之整合mybatis

Spring整合mybatis回顾

原生Spring中整合mybatis主要是将SqlSessionFactoryBean交给Spring管理。下面来回顾一下

1. 引入依赖

	<dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>2.1.0</version></dependency><!-- MyBatis --><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.10</version></dependency><!-- MySQL Connector --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.27</version></dependency>

2. mybatis-config.xml

<!-- DataSource配置 --><bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"><property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/><property name="url" value="jdbc:mysql://192.168.56.102:3306/boot-test"/><property name="username" value="root"/><property name="password" value="123456"/></bean><!-- MyBatis SqlSessionFactory配置 --><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource" ref="dataSource"/><property name="mapperLocations" value="classpath:mapper/*Mapper.xml"/></bean><!-- MyBatis SqlSessionTemplate配置 --><bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate"><constructor-arg index="0" ref="sqlSessionFactory"/></bean><!-- Mapper接口扫描 --><bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"><property name="basePackage" value="cn.axj.mybatis.mapper"/></bean><!-- 事务管理器配置 --><bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"><property name="dataSource" ref="dataSource"/></bean><!--    开启事务管理器--><tx:annotation-driven transaction-manager="transactionManager"/>

Spring整合mybatis需要配置数据源，事务管理器，显示的开启事务管理器，sqlSessionFacotryBean。感觉整个配置下来巨麻烦不说，还特别容易忘记。

SpringBoot整合mybatis

想比之下，SpringBoot默认帮我们开启了事务管理器，默认帮我们将sqlSessionFacotryBean注册到Spring容器中。我们只需要配置mapper.xml的文件路径以及mapper接口的路径(接口路径可不配置，但是需要在mapper接口上显示的加上@Mapepr注解)和数据库链接参数等信息。

涉及到SpringBoot的自动配置原理，以后再说。

1.引入依赖

		<dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>2.2.2</version></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid-spring-boot-starter</artifactId><version>1.2.16</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId></dependency>

mybatis-spring-boot-starter 可以简化在 Spring Boot 项目中集成 MyBatis 的过程，并且事务管理也会自动配置。在 Spring Boot 2.x 及以上版本中，只需添加相应的依赖和配置，即可启用事务管理。

2. 配置数据源和 MyBatis 属性

spring:datasource:druid:username: rootpassword: 123456url: jdbc:mysql://192.168.56.102:3306/boot-test?driver-class-name: com.mysql.cj.jdbc.Driverinitial-size: 5min-idle: 5max-active: 20max-wait: 60000time-between-eviction-runs-millis: 60000min-evictable-idle-time-millis: 300000validation-query: select 1 from dualtest-while-idle: truetest-on-borrow: falsetest-on-return: false
mybatis:mapper-locations: classpath:mapper/*.xmltype-aliases-package: cn.axj.boot.mybatis.model.beanconfiguration:map-underscore-to-camel-case: true

3. 配置 Mapper 接口

确保你的 Mapper 接口和 XML 映射文件配置正确。例如，创建一个简单的 Mapper 接口

@Mapper
public interface SysUserMapper {int insertUser(SysUser sysUser);SysUser getUserById(Integer id);
}

可通过在SpringBoot配置类上手动加上@MapperScan(basePackages = “cn.axj.boot.mybatis.mapper”)定义mapper接口路径，在创建mapper接口的时候可不用加上@Mapper注解

4. 配置mapper.xml

按照配置在resources目录下创建mapper文件夹，创建一个简单的mapper.xml文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="cn.axj.boot.mybatis.mapper.SysUserMapper"><insert id="insertUser">insert into sys_user(id, name, age) values(#{id}, #{name}, #{age})</insert><select id="getUserById" resultType="cn.axj.boot.mybatis.model.bean.SysUser">select * from sys_user where id = #{id}</select>
</mapper>

5. 使用 @Transactional 注解

@Service
public class SysUserService {@Resourceprivate SysUserMapper sysUserMapper;@Transactional(rollbackFor = Exception.class)public void testTrans(){SysUser sysUser = new SysUser();sysUser.setName("test");sysUser.setAge(23);sysUserMapper.insertUser(sysUser);int i = ThreadLocalRandom.current().nextInt(10);SysUser userById = sysUserMapper.getUserById(i);if(Objects.isNull(userById)){throw new RuntimeException("查询结果为空");}}
}