Spring Boot整合MyBatis全攻略：原理剖析与最佳实践

MyBatis作为Java生态中最流行的ORM框架之一，与Spring Boot的结合极大地简化了数据库访问层的开发。本文将深入剖析Spring Boot整合MyBatis的核心机制，详细介绍各种使用方式，并分享实际开发中的高级技巧和最佳实践。

一、Spring Boot与MyBatis整合概述

1.1 整合背景与优势

传统Spring项目中整合MyBatis需要配置大量XML和Bean，而Spring Boot通过自动配置和starter机制，实现了"开箱即用"的MyBatis集成体验。主要优势包括：

• 零XML配置：基于注解和Java Config的配置方式

• 自动配置：自动发现DataSource、SqlSessionFactory等

• 简化分页：内置分页插件支持

• 强大扩展：支持通用Mapper、MyBatis-Plus等增强工具

1.2 官方支持的整合方式

Spring Boot官方提供了两种MyBatis整合方式：

1. 经典模式：使用mybatis-spring-boot-starter

2. 注解模式：使用mybatis-spring-boot-starter + 注解配置

二、快速整合实战

2.1 基础环境搭建

步骤1：添加Maven依赖

<dependencies><!-- Spring Boot Starter --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId></dependency><!-- MyBatis Starter --><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>2.3.0</version></dependency><!-- 数据库驱动 --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope></dependency><!-- 其他必要依赖 --><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional></dependency>
</dependencies>

步骤2：配置数据源

spring:datasource:url: jdbc:mysql://localhost:3306/mybatis_demo?useSSL=false&serverTimezone=UTC&characterEncoding=utf8username: rootpassword: 123456driver-class-name: com.mysql.cj.jdbc.Driver

2.2 自动配置原理剖析

Spring Boot通过MybatisAutoConfiguration类实现自动配置，核心机制包括：

1. SqlSessionFactory自动创建：基于配置的DataSource

2. Mapper扫描注册：通过@MapperScan或@Mapper注解

3. 事务管理集成：与Spring事务无缝整合

关键自动配置属性：

mybatis:config-location: classpath:mybatis/mybatis-config.xml  # 全局配置文件路径mapper-locations: classpath:mybatis/mapper/*.xml      # Mapper XML文件位置type-aliases-package: com.example.model              # 类型别名包configuration:                                       # MyBatis配置项map-underscore-to-camel-case: true                 # 下划线转驼峰default-fetch-size: 100default-statement-timeout: 30

三、MyBatis基础使用

3.1 注解方式开发

实体类：

@Data
public class User {private Long id;private String username;private String email;private LocalDateTime createTime;
}

Mapper接口：

@Mapper
public interface UserMapper {@Select("SELECT * FROM user WHERE id = #{id}")User selectById(Long id);@Insert("INSERT INTO user(username, email, create_time) " +"VALUES(#{username}, #{email}, #{createTime})")@Options(useGeneratedKeys = true, keyProperty = "id")int insert(User user);@Update("UPDATE user SET username=#{username}, email=#{email} WHERE id=#{id}")int update(User user);@Delete("DELETE FROM user WHERE id=#{id}")int delete(Long id);@Select("SELECT * FROM user")List<User> selectAll();
}

3.2 XML方式开发

Mapper接口：

@Mapper
public interface UserMapper {User selectById(Long id);int insert(User user);int update(User user);int delete(Long id);List<User> selectAll();
}

XML映射文件 (resources/mapper/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="com.example.mapper.UserMapper"><resultMap id="userResultMap" type="User"><id property="id" column="id"/><result property="username" column="username"/><result property="email" column="email"/><result property="createTime" column="create_time"/></resultMap><select id="selectById" resultMap="userResultMap">SELECT * FROM user WHERE id = #{id}</select><insert id="insert" useGeneratedKeys="true" keyProperty="id">INSERT INTO user(username, email, create_time)VALUES(#{username}, #{email}, #{createTime})</insert><update id="update">UPDATE user SET username=#{username}, email=#{email}WHERE id=#{id}</update><delete id="delete">DELETE FROM user WHERE id=#{id}</delete><select id="selectAll" resultMap="userResultMap">SELECT * FROM user</select>
</mapper>

3.3 动态SQL应用

MyBatis提供了强大的动态SQL功能：

<select id="selectByCondition" resultMap="userResultMap">SELECT * FROM user<where><if test="username != null and username != ''">AND username LIKE CONCAT('%', #{username}, '%')</if><if test="email != null and email != ''">AND email = #{email}</if><if test="startTime != null">AND create_time >= #{startTime}</if><if test="endTime != null">AND create_time <= #{endTime}</if></where>ORDER BY id DESC
</select>

对应Mapper接口：

List<User> selectByCondition(@Param("username") String username,@Param("email") String email,@Param("startTime") LocalDateTime startTime,@Param("endTime") LocalDateTime endTime);

四、高级特性与集成

4.1 分页插件集成

步骤1：添加PageHelper依赖

<dependency><groupId>com.github.pagehelper</groupId><artifactId>pagehelper-spring-boot-starter</artifactId><version>1.4.6</version>
</dependency>

步骤2：配置分页参数

pagehelper:helper-dialect: mysqlreasonable: truesupport-methods-arguments: true

步骤3：使用分页查询

public PageInfo<User> getUsers(int pageNum, int pageSize) {PageHelper.startPage(pageNum, pageSize);List<User> users = userMapper.selectAll();return new PageInfo<>(users);
}

4.2 多数据源配置

@Configuration
@MapperScan(basePackages = "com.example.mapper.primary", sqlSessionFactoryRef = "primarySqlSessionFactory")
public class PrimaryDataSourceConfig {@Bean@Primary@ConfigurationProperties("spring.datasource.primary")public DataSource primaryDataSource() {return DataSourceBuilder.create().build();}@Bean@Primarypublic SqlSessionFactory primarySqlSessionFactory(@Qualifier("primaryDataSource") DataSource dataSource) throws Exception {SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();factoryBean.setDataSource(dataSource);factoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/primary/*.xml"));return factoryBean.getObject();}@Bean@Primarypublic DataSourceTransactionManager primaryTransactionManager(@Qualifier("primaryDataSource") DataSource dataSource) {return new DataSourceTransactionManager(dataSource);}
}// 类似配置第二个数据源（去掉@Primary注解）

4.3 事务管理

Spring Boot自动配置了基于Spring的事务管理，只需使用@Transactional注解：

@Service
public class UserService {private final UserMapper userMapper;private final LogMapper logMapper;public UserService(UserMapper userMapper, LogMapper logMapper) {this.userMapper = userMapper;this.logMapper = logMapper;}@Transactionalpublic void createUserWithLog(User user, String operation) {userMapper.insert(user);Log log = new Log();log.setOperation(operation);log.setCreateTime(LocalDateTime.now());logMapper.insert(log);// 如果此处抛出异常，两个插入操作都会回滚}
}

五、性能优化与最佳实践

5.1 SQL优化建议

1. **避免SELECT ***：只查询需要的字段

2. 合理使用索引：通过EXPLAIN分析SQL执行计划

3. 批量操作：使用<foreach>标签实现批量插入/更新

<insert id="batchInsert">INSERT INTO user(username, email, create_time) VALUES<foreach collection="users" item="user" separator=",">(#{user.username}, #{user.email}, #{user.createTime})</foreach>
</insert>

5.2 缓存配置

一级缓存：SqlSession级别，默认开启
二级缓存：Mapper级别，需要显式开启：

<mapper namespace="com.example.mapper.UserMapper"><cache eviction="LRU" flushInterval="60000" size="512" readOnly="true"/>...
</mapper>

与Spring Cache集成：

@CacheConfig(cacheNames = "users")
public interface UserMapper {@Cacheable(key = "#id")@Select("SELECT * FROM user WHERE id = #{id}")User selectById(Long id);@CacheEvict(allEntries = true)@Update("UPDATE user SET username=#{username} WHERE id=#{id}")int updateUsername(@Param("id") Long id, @Param("username") String username);
}

5.3 监控与诊断

1. 慢SQL监控：配置mybatis.configuration.log-impl为SLF4J

2. SQL执行时间统计：使用P6Spy或Druid的Filter

3. MyBatis指标：与Spring Boot Actuator集成

management:endpoints:web:exposure:include: health,info,metricsmetrics:tags:application: ${spring.application.name}

六、常见问题解决方案

6.1 映射问题

问题：数据库字段与Java属性不匹配
解决：

1. 使用@Result注解或<resultMap>显式映射

2. 配置mybatis.configuration.map-underscore-to-camel-case=true

6.2 事务不生效

问题：@Transactional注解无效
排查：

1. 检查是否在同一个类中调用

2. 确认方法是否为public

3. 检查异常类型是否被捕获未抛出

6.3 性能问题

问题：批量操作性能差
优化：

1. 使用ExecutorType.BATCH模式

2. 合理设置batchSize

3. 考虑使用MyBatis-Plus的AR模式

@Autowired
private SqlSessionTemplate sqlSessionTemplate;public void batchInsert(List<User> users) {SqlSession session = sqlSessionTemplate.getSqlSessionFactory().openSession(ExecutorType.BATCH, false);try {UserMapper mapper = session.getMapper(UserMapper.class);for (User user : users) {mapper.insert(user);}session.commit();} finally {session.close();}
}

七、MyBatis-Plus扩展

MyBatis-Plus是MyBatis的增强工具，提供了更多便捷功能：

7.1 快速入门

添加依赖：

<dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.5.3.1</version>
</dependency>

实体类：

@Data
@TableName("user")
public class User {@TableId(type = IdType.AUTO)private Long id;private String username;private String email;private LocalDateTime createTime;
}

Mapper接口：

public interface UserMapper extends BaseMapper<User> {// 已包含基本的CRUD方法
}

7.2 强大功能

1. 条件构造器：

QueryWrapper<User> query = new QueryWrapper<>();
query.like("username", "张").between("create_time", startDate, endDate).orderByDesc("id");
List<User> users = userMapper.selectList(query);

      2.Lambda表达式

LambdaQueryWrapper<User> lambdaQuery = new LambdaQueryWrapper<>();
lambdaQuery.like(User::getUsername, "张").ge(User::getCreateTime, startDate).select(User::getId, User::getUsername);
List<User> users = userMapper.selectList(lambdaQuery);

      3.自动填充 

@TableField(fill = FieldFill.INSERT)
private LocalDateTime createTime;@TableField(fill = FieldFill.INSERT_UPDATE)
private LocalDateTime updateTime;

 

结语

Spring Boot与MyBatis的整合为Java开发者提供了高效、灵活的数据访问解决方案。通过本文的介绍，您应该已经掌握了从基础配置到高级特性的全面知识。在实际项目中，建议：

1. 根据项目规模选择合适的开发模式（注解/XML）

2. 合理利用MyBatis的动态SQL能力

3. 关注性能优化，特别是批量操作场景

4. 考虑使用MyBatis-Plus等增强工具提升开发效率

希望本文能帮助您在Spring Boot项目中更好地使用MyBatis，构建健壮高效的数据访问层。