Mybatis-Spring的整合

一、在pom.xml中导入常用jar包

<dependencies>
         <!--测试类-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>

        <!--mysql-connector-java-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>

        <!--spring相关-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.1.10.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.1.10.RELEASE</version>
        </dependency>

        <!--aspectJ AOP 织入器-->
        <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.4</version>
        </dependency>

        <!--mybatis-spring整合包 【重点】-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.2</version>
        </dependency>

         <!--自动生成getter setter方法等-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.18</version>
        </dependency>
    </dependencies>

<!--配置Maven静态资源过滤问题！-->
    <build>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>

二、编写配置文件

• mybatis-config.xml

<?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核心配置-->
<configuration>

    <typeAliases>
        <package name="com.zhou.pojo"/>
    </typeAliases>

    <!--可以将settings写在这里-->

</configuration>

• spring_dao.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"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop
       http://www.springframework.org/schema/aop/spring-aop.xsd">

    <!--DataSource:使用Spring的数据源替换Mybatis的配置
    此处使用Spring提供的jdbc-->
    <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=true&amp;useUnicode=true&amp;characterEncoding=utf8"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
    </bean>

    <!--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/zhou/mapper/*.xml"/>
    </bean>

    <!--sqlSessionTemplate就是sqlSession-->
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <!--只能通过构造器注入sqlSqqeionFactory-->
        <constructor-arg index="0" ref="sqlSessionFactory"/>
    </bean>

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

step: 1、配置数据源DataSource 相当于mybatis中的jdbc.properties文件
2、配置sqlSessionFactory。关联mybatis,在其中可以实现mybatis的几乎全部功能
3、注册sqlSessionTemplate，关联sqlSessionFactory

三、写一个mapper接口

public interface UserMapper {
    public List<User> selectUser();
}

四、增加mapper接口的实现类；私有化sqlSessionTemplate

public class UserDaoImpl implements UserMapper {

    //原来所有东西都用sqlSession来执行 现在都使用SqlSessionTemplate
   //sqlSession不用我们自己创建了，Spring来管理
   private SqlSessionTemplate sqlSession;

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

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

五、在spring_dao中注册bean实现，就是上面的

    <bean id="UserMapper" class="com.zhou.mapper.UserMapperImpl">
        <property name="sqlSession" ref="sqlSession"/>
    </bean>

六、测试

@Test
    public void test() {
        ApplicationContext context = new ClassPathXmlApplicationContext("spring_dao.xml");
        UserMapper mapper = context.getBean("UserMapper2", UserMapper.class);
        for (User user : mapper.selectUser()) {
            System.out.println(user);
        }
    }

第二种：
mybatis-spring1.2.3版以上的才有这个 .

官方文档截图 :

dao继承Support类 , 直接利用 getSqlSession() 获得 , 然后直接注入SqlSessionFactory . 比起方式1 , 不需要管理SqlSessionTemplate , 而且对事务的支持更加友好 . 可跟踪源码查看

测试：

1、将我们上面写的UserDaoImpl修改一下

public class UserDaoImpl extends SqlSessionDaoSupport implements UserMapper {
   public List<User> selectUser() {
       UserMapper mapper = getSqlSession().getMapper(UserMapper.class);
       return mapper.selectUser();
  }
}

2、修改bean的配置

<bean id="userDao" class="com.kuang.dao.UserDaoImpl">
   <property name="sqlSessionFactory" ref="sqlSessionFactory" />
</bean>

3、测试

@Test
public void test2(){
   ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
   UserMapper mapper = (UserMapper) context.getBean("userDao");
   List<User> user = mapper.selectUser();
   System.out.println(user);
}

总结 : 整合到spring以后可以完全不要mybatis的配置文件，除了这些方式可以实现整合之外，我们还可以使用注解来实现，这个等我们后面学习SpringBoot的时候还会测试整合！