springboot整合mybatis打印sql（包含一个坑）

╰+攻爆jí腚メ 2023-01-20 11:49 3阅读 0赞

# maven依赖 #

<dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.1.1</version>
    </dependency>

# 整合Mybatis的两种方式 #

## 手动装配SqlSessionFactoryBean ##

**注意：使用手动装配`SqlSessionFactoryBean`，一定要注意，`application.yml`中的`mybatis`配置是无效的，所有`mybatis`的配置都需要在代码中配置。**

### Bean配置类 ###

@Configuration
    public class MybatisConfig { 
        @Bean
        public SqlSessionFactoryBean getSqlSessionFactoryBean(DataSource dataSource) throws IOException { 
            SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
            sqlSessionFactoryBean.setDataSource(dataSource);
            sqlSessionFactoryBean.setConfigLocation(new ClassPathResource("mybatis-config.xml"));
            sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mapper/*Mapper.xml"));
            return sqlSessionFactoryBean;
        }
    }

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### mybatis-config.xml配置sql打印 ###

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE configuration
            PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-config.dtd">
    <configuration>
        <settings>
            
            <setting name="logImpl" value="STDOUT_LOGGING" />
        </settings>
    </configuration>

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMwMDM4MTEx_size_16_color_FFFFFF_t_70 1]

## 自动装配MybatisAutoConfiguration ##

**注意：没有自定义`SqlSessionFactoryBean`时，Springboot会使用`MybatisAutoConfiguration`自动装配`SqlSessionFactoryBean`，mybatis的配置项需要在application.yml配置。**

### MybatisAutoConfiguration源码 ###

@Bean
    @ConditionalOnMissingBean
    public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception { }

### application.yml配置sql打印 ###

注释的内容同样可以达到效果，只是额外需要`mybatis-config.xml`配置文件

#mybatis:
    # config-location: classpath:mybatis-config.xml
    # mapper-locations: classpath:mapper/*Mapper.xml
    mybatis:
      configuration:
        log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
      mapper-locations: classpath:mapper/*Mapper.xml

# 一个坑 #

**网上的博客基本上都是说在`application.yml`中配置`mybatis`，就可以打印`sql`，但是前提是使用`Springboot`自动装配的`MybatisAutoConfiguration`时，才有效。因为`application.yml`中的`mybatis`配置是针对自动装配时生效。**

# 启动类 #

@SpringBootApplication
    @ComponentScan(basePackages = { "com.edu.*"})
    @MapperScan(basePackages = { "com.edu.dao"})
    @EnableTransactionManagement
    @EnableAspectJAutoProxy(proxyTargetClass = true)
    public class Application { 
        public static void main(String[] args) { 
            SpringApplication.run(Application.class, args);
        }
    }

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