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Spring整合Mybatis

news 2025/4/28 18:46:41

本文介绍Spring整合Mybatis的步骤，对整合目标做如下说明：

数据源采用druid
基于Mybatis Mapper 接口方式实现数据库CRUD
采用注解方式实现Spring 声明式事务

完成上述目标，需要如下步骤：

1、增加项目依赖【pom.xml】

重点依赖说明：spring-context是spring的核心、AOP需要aspectjweaver支持，事务管理器需要spring-jdbc，mybatis-spring 是spring整合mybatis的核心，druid是数据源

        <dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>5.2.20.RELEASE</version></dependency><dependency><groupId>org.aspectj</groupId><artifactId>aspectjweaver</artifactId><version>1.9.6</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>5.3.8</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.1</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>2.0.6</version></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.16</version></dependency><dependency><groupId>ch.qos.logback</groupId><artifactId>logback-classic</artifactId><version>1.2.3</version></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.0</version><scope>provided</scope></dependency><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.2.6</version></dependency></dependencies>

2、spring和mybatis配置文件配置【applicationContext.xml、mybatis-config.xml】

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:context="http://www.springframework.org/schema/context"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:task="http://www.springframework.org/schema/task"xmlns:tx="http://www.springframework.org/schema/tx"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsdhttp://www.springframework.org/schema/taskhttp://www.springframework.org/schema/task/spring-task.xsdhttp://www.springframework.org/schema/txhttp://www.springframework.org/schema/tx/spring-tx.xsd"><context:component-scan base-package="com.text"/><!--MyBatis与Spring的整合配置 --><!--数据源--><bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"><property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/><property name="url" value="jdbc:mysql://xxx:3306/xxx?useUnicode=true&amp;characterEncoding=UTF-8"/><property name="username" value="xxx"/><property name="password" value="xxx"/><property name="initialSize" value="5"/><property name="maxActive" value="20"/></bean><!--SessionFactoryBean--><bean id="sessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource" ref="dataSource"/><property name="mapperLocations" value="classpath:mappers/*.xml"/><property name="configLocation" value="classpath:mybatis-config.xml"/></bean><!--配置Mapper扫描器--><bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"><property name="basePackage" value="com.text.mapper"/></bean><!--定义事务管理器--><bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"><property name="dataSource" ref="dataSource"/></bean><!--开启事务注解 --><tx:annotation-driven transaction-manager="transactionManager"/>
</beans>

重点配置介绍：

component-scan 注解扫描的包
dataSource 数据源配置
sessionFactory mybatis的核心类，交给spring IOC容器管理生成，里面包含mybatis的配置文件和mapper接口的xml实现文件
MapperScannerConfigurer mapper 接口扫描包，如项目中的StudentMapper
transactionManager 定义事务管理器
tx:annotation-driven 开启事务注解

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration><settings><!-- 驼峰命名转换 --><setting name="mapUnderscoreToCamelCase" value="true"/></settings>
</configuration>

3、定义数据库实体、Mapper接口及对应的mapper.xml文件

以简单的学生表为例

CREATE TABLE `student` (`id` varchar(100) COLLATE utf8mb4_bin NOT NULL,`name` varchar(100) COLLATE utf8mb4_bin DEFAULT NULL,`age` int DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;

java实体：

package com.text.entity;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;@Data
@AllArgsConstructor
@NoArgsConstructor
public class Student {private String id;private String name;private int age;}

Mapper接口【StudentMapper.java】：

package com.text.mapper;
import com.text.entity.Student;
import java.util.List;public interface StudentMapper {List<Student> selectAll() throws Exception;void save(Student student) throws Exception;
}

Mapper.xml文件【student.xml】：

<?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="com.text.mapper.StudentMapper"><select id="selectAll" resultType="com.text.entity.Student">select * from student</select><insert id="save" parameterType="com.text.entity.Student">INSERT INTO student(id, name, age) VALUES(#{id},#{name},#{age});</insert>
</mapper>

重点配置说明：namespace需要是接口StudentMapper的完整路径名，id需要是接口的方法名

4、服务接口及实现【StudentService.java、StudentServiceImpl.java】

package com.text.service;public interface StudentService {public void batchInsert() throws Exception;
}

package com.text.service;import com.text.entity.Student;
import com.text.mapper.StudentMapper;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;import javax.annotation.Resource;@Transactional(rollbackFor = Exception.class)
@Service
public class StudentServiceImpl implements StudentService{@Resourceprivate StudentMapper studentMapper;@Overridepublic void batchInsert() throws Exception {for(int i=10;i<20;i++) {if(i==13) {throw new Exception("模拟抛出异常");}Student student = new Student(i+"","张三"+i,i);studentMapper.save(student);}}public StudentMapper getStudentMapper() {return studentMapper;}public void setStudentMapper(StudentMapper studentMapper) {this.studentMapper = studentMapper;}
}

重点代码说明：

@Transactional(rollbackFor = Exception.class) service实现类的所有方法添加事务支持，方法发现抛出异常，事务回滚
private StudentMapper studentMapper 方法内部注入的Mapper接口，后面的Debug程序可以看出，studentMapper对象实际是代理对象，代理对象内部存在SqlSession；mybatis单独使用不集成spring时，在service层面使用Mapper时对数据库操作时，需要如下代码：

SqlSession sqlSession = MyBatisUtils.openSession();
StudentMapper mapper = sqlSession.getMapper(StudentMapper.class);
List<Student> students = mapper.selectAll();

集成了spring后，service层只需要注入studentMapper 接口即可，实际注入的代理对象，通过代理对象操作接口方法，接口方法需要sqlSession操作数据库，代理对象存在此对象，最终也就实现了对数据库的操作

5、测试类及运行结果

package com.text;import com.text.service.StudentService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class Application {public static void main(String[] args) throws Exception {ApplicationContext context = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");StudentService studentService = context.getBean("studentServiceImpl", StudentService.class);System.out.println("============" + studentService);studentService.batchInsert();}
}

重点代码说明：

context.getBean("studentServiceImpl", StudentService.class); service层被@Transactional事务声明，此对象是jdk的动态代理对象
studentService 内部的被代理对象（目标对象）中的studentMapper 对象实际也是代理对象

运行结果：