Spring Boot 集成 MyBatis 与 c3p0

*对应的目录结构

一、添加依赖

    <!-- 添加对 mybatis 的依赖 --><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>1.1.1</version></dependency><!-- 添加对 JDBC 的支持 --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-jdbc</artifactId></dependency><!-- 添加数据库驱动 --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId></dependency><!-- 添加 c3p0 数据源 --><dependency><groupId>c3p0</groupId><artifactId>c3p0</artifactId><version>0.9.1.2</version></dependency>

二、配置数据源与 SqlSessionFactory

1.通过 application.properties 配置文件进行配置

# 设置数据库相关
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/springboot
spring.datasource.username=root
spring.datasource.password=1234# 设置 c3p0 数据源
spring.datasource.type=com.mchange.v2.c3p0.ComboPooledDataSource# 设置 MyBatis mapper 的别名所在的包
mybatis.type-aliases-package=com.jas.mapper
# 设置 mapper 接口对应 XMl 配置文件的路径
mybatis.mapper-locations=classpath:mapperConfig/*.xml

2.通过配置类进行配置

application.properties 配置文件设置相关变量

# 设置数据库相关属性
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/springboot
spring.datasource.username=root
spring.datasource.password=1234# 设置，mapper 接口路径，mapper 接口对应的 xml 配置文件
mapper.package.path=com.jas.mapper
mapper.xml.config.path=/mapperConfig/*.xml

DataSourceConfiguration 类配置 c3p0 数据源

@SpringBootConfiguration
public class DataSourceConfiguration {@Value("${spring.datasource.driver-class-name}")private String jdbcDriver;@Value("${spring.datasource.url}")private String jdbcUrl;@Value("${spring.datasource.username}")private String jdbcUser;@Value("${spring.datasource.password}")private String jdbcPassword;@Beanpublic DataSource createDataSource() throws PropertyVetoException {ComboPooledDataSource dataSource = new ComboPooledDataSource();dataSource.setDriverClass(jdbcDriver);dataSource.setJdbcUrl(jdbcUrl);dataSource.setUser(jdbcUser);dataSource.setPassword(jdbcPassword);// 关闭连接后不自动提交dataSource.setAutoCommitOnClose(false);return dataSource;}
}

SqlSessionFactoryBean 类配置 SqlSessionFactory

@SpringBootConfiguration
public class SessionFactoryConfiguration {@Value("${mapper.xml.config.path}")private String mapperXMLConfigPath;@Value("${mapper.package.path}")private String mapperPackagePath;@Autowiredprivate DataSource dataSource;@Beanpublic SqlSessionFactoryBean createSqlSessionFactory() throws IOException {SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();String packageXMLConfigPath = PathMatchingResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX + mapperXMLConfigPath;// 设置 mapper 对应的 XML 文件的路径sqlSessionFactoryBean.setMapperLocations(resolver.getResources(packageXMLConfigPath));// 设置数据源sqlSessionFactoryBean.setDataSource(dataSource);// 设置 mapper 接口所在的包sqlSessionFactoryBean.setTypeAliasesPackage(mapperPackagePath);return sqlSessionFactoryBean;}
}

三、编写代码

User 类

public class User {private Integer userId;private String username;private Integer age;private char gender;/** 省略 get 与 set 方法*/
}

UserMapper 接口

/** 只定义了一个简单的测试方法*/
@Mapper
public interface UserMapper {User getUser(Integer id);
}

userMapper.xml配置文件

<?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.jas.mapper.UserMapper"><select id="getUser" resultType="com.jas.domain.User">SELECT * FROM user WHERE userId = #{userId}</select>
</mapper>

四、编写测试的 Controller

@RestController
public class UserController {@Autowiredprivate UserMapper userMapper;@GetMapping("/user/{userId}")public User getUser(@PathVariable Integer userId){User user = userMapper.getUser(userId);return user;}
}

五、入口类代码 (验证 c3p0 数据源是否生效)

/** 注意：入口类要能扫描到对应的 Bean*/
@SpringBootApplication
public class App {public static void main(String[] args) {ConfigurableApplicationContext context = SpringApplication.run(App.class, args);DataSource dataSource = context.getBean(DataSource.class);System.out.println(dataSource.getClass());}
}

六、测试结果

控制台输出：可以看出 c3p0 数据源已经生效

浏览器访问测试的 Controller

这篇博文记录基于 XML 配置文件的 MyBatis 使用步骤。如果是基于注解的话，直接在对应的 mapper 接口方法上加上对应的注解即可。

PS ：打印 SQL 日志

只需要在application.properties 配置文件中设置logging.level.包名=debug即可

# com.jas.mapper 是 mapper 接口所在的包
logging.level.com.jas.mapper=debug

当访问测试 Controller 时，控制台会输出 SQL 语句

重写了一下 Spring Boot 整合 MyBatis 的 demo，基于注解与配置文件两种形式，使用的是 druid 数据源，并配置了 druid 监控中心。点我查看源码~