[Java知识库]Mybatis高级【三】

mybatis与spring整合

整合流程：

1.引入Spring配置文件applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">

</beans>

2.配置数据源替换mybaits的数据源

<!--配置数据源：数据源有非常多，可以使用第三方的，也可使使用Spring的-->
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
    <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=false&amp;useUnicode=true&amp;characterEncoding=utf8"/>
    <property name="username" value="root"/>
    <property name="password" value="xxc113206"/>
</bean>

3.配置SqlSessionFactory，关联MyBatis

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="dataSource"/>
    <!--关联Mybatis-->
    <property name="configLocation" value="classpath:mybatis-config.xml"/>
    <property name="mapperLocations" value="classpath:com/xxc/dao/*.xml"/>
</bean>

4.使用MapperScannerConfigurer配置basePackage（mapper包里mapper接口，会自动实例化mapper对象。直接@Autowrited即可）

<bean id="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="xyz.javaswing.mapper"/>
    </bean>

spring中配置mybatis的配置文件，mybatis大部分文件是不需要单独配置了，除了setting中的配置。

SqlSessionFactoryBean源码分析

初始化mybatis，初始化configuration对象，将configuration对象注入到spring中

MapperFactoryBean源码分析

将dao接口注入到spring中

在容器初始化时，确保mapper接口被注册到mapperRegistry中

MapperScannerConfiguration源码分析

org.mybatis.spring.mapper.MapperScannerConfigurer

实现BeanDefinitionRegistryPostProcessor接口实现bean初始化时就能修改bean的元信息

MapperScannerConfigurer主要作用是将dao接口转换成mapeprFactoryBean，并注入到容器中

public class MapperScannerConfigurer implements BeanDefinitionRegistryPostProcessor, InitializingBean, ApplicationContextAware, BeanNameAware {
    private String basePackage;//指定要扫描的包
    private boolean addToConfig = true;
    private String lazyInitialization;
    private SqlSessionFactory sqlSessionFactory;
    private SqlSessionTemplate sqlSessionTemplate;
    private String sqlSessionFactoryBeanName;
    private String sqlSessionTemplateBeanName;
    private Class<? extends Annotation> annotationClass;//mapper及饿哦库上有指定的annotation才会被扫描
    private Class<?> markerInterface;//mapper接口实现指定接口才会被扫描
    private Class<? extends MapperFactoryBean> mapperFactoryBeanClass;
    private ApplicationContext applicationContext;//容器上下文
    private String beanName;
    private boolean processPropertyPlaceHolders;
    private BeanNameGenerator nameGenerator;
    }

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