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; @Bean public 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; @Autowired private DataSource dataSource; @Bean public 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 { @Autowired private 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~