12、整合Mybatis

导包

<dependencies>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.3.25</version>
    </dependency>


    <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>5.3.25</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.9.6</version>

    </dependency>


    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.11</version>

    </dependency>

    <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.47</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.2</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>5.3.24</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>5.3.24</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis-spring</artifactId>
        <version>2.0.6</version>
    </dependency>



</dependencies>

12.1、回顾Mybatis

1. 编写实体类

    

2. 编写核心配置文件

    

3. 编写接口

    

4. 编写mapper.xml

    

5. 测试

12.2、Spring集成Mybatis

首先 将驱动链接配置进行注入

<!--    配置mysql驱动链接-->
   <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
       <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
       <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=false&amp;useUnique=true*&amp;characterEncoding=UTF-8&amp;serverTimezone=GMT"></property>
       <property name="username" value="root"></property>
       <property name="password" value="123456"></property>
   </bean>

接着将sqlsession工厂进行注入和mybatis配置文件绑定以及mapper绑定

<!--sqlSessionFactory-->

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
<!--        绑定mybatis的配置文件-->
        <property name="configLocation" value="classpath:mybatis-config.xml"></property>
<!--        mapper 绑定-->
        <property name="mapperLocations" value="classpath:com/an/mapper/*.xml"></property>
    </bean>

接着利用一个实现类来实现对sqlsession的注入

public class UserMapperImpl implements UserMapper{


    private SqlSessionTemplate sqlSession;

    public void setSqlSession(SqlSessionTemplate sqlSession) {
        this.sqlSession = sqlSession;
    }

    @Override
    public List<User> selectUser() {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
       return mapper.selectUser();
    }
}

注册sqlsession的bean

<bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
    <constructor-arg index="0" ref="sqlSessionFactory"/>
</bean>

因为SqlSessionTemplate类的构造方法需要传入一个sqlSessionFactory 所以我们利用一个Bean来进行sqlSessionFactory 的注入

之后注册实现类

<?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">

    <import resource="spring-dao.xml"/>

    <bean id="userMapper" class="com.an.mapper.UserMapperImpl">
        <property name="sqlSession" ref="sqlSession"></property>
    </bean>
</beans>

测试

public class MyTest {
    @Test
    public void test() throws IOException {
      ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserMapper userMapper = context.getBean("userMapper", UserMapper.class);


        List<User> userList = userMapper.selectUser();
        for (User user : userList) {
            System.out.println(user);
        }


    }
}

这里面有两个重要的配置

<!--sqlSessionFactory-->

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
<!--        绑定mybatis的配置文件-->
        <property name="configLocation" value="classpath:mybatis-config.xml"></property>
<!--        mapper 绑定-->
        <property name="mapperLocations" value="classpath:com/an/mapper/*.xml"></property>
    </bean>


    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <constructor-arg index="0" ref="sqlSessionFactory"/>
    </bean>

SqlSessionTemplate

SqlSessionTemplate 是 MyBatis-Spring 的核心。作为 SqlSession 的一个实现，这意味着可以使用它无缝代替你代码中已经在使用的 SqlSession。 SqlSessionTemplate 是线程安全的，可以被多个 DAO 或映射器所共享使用。

第二种方法是利用继承SqlSessionDaoSupport类来直接使用getsqlsession方法来直接获得sqlsession对象省去了第一种方法中间注入sqlSession的步骤

但是还是推荐使用第一种方法