8、整合MyBatis

步骤

1.导入相关jar包

junit\mybatis\mysql数据库\spring相关\aop织入\mybatis-spring(new)

2.编写配置文件

3.测试

8.1回忆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

8.2Spring整合Mybatis

8.2.1方式一

1.编写数据源配置(spring-dao.xml)

2.sqlSessionFactory

3.sqlSessionTemplate

spring-dao.xml配置文件只专注于数据源的配置,这个文件基本是固定的,然后因为Mybatis被Spring内部整合了,所以其核心配置文件mybatis-config.xml现在只做别名和Mybatis设置;为了更加体现分工明确,我们在Spring的核心配置文件applicationContext.xml中引入spring-dao.xml,并且在其中完成相关Mapper的注册

• spring-dao.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans 
    <!--DataSource:使用Spring的数据源替换Mybatis的配置  c3p0 dbcp druid 我们这里使用Spring提供的JDBC:org.springframework.jdbc.datasorce-->
    <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=UTF-8"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
    </bean>
    <!--配置sqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <!--绑定mybatis核心配置文件-->
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:com/dong/mapper/*.xml"/>
    </bean>
    <!--SqlSessionTemplate:就是我们 以前使用的sqlSession-->
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <!--只能使用构造器注入 sqlSessionFactory,因为它没有set方法-->
        <constructor-arg index="0"  ref="sqlSessionFactory"/>
    </bean>
</beans>

• 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>
    <typeAliases>
        <package name="com.dong.pojo"/>
    </typeAliases>
</configuration>

4.需要给接口增加实现类

• UserMapperImpl.class

public class UserMapperImpl implements UserMapper{
    //在原来我们的所有操作都使用sqlSession来执行,现在都是使用SqlSessionTemplate
    private SqlSessionTemplate sqlSession;
    public void setSqlSession(SqlSessionTemplate sqlSession) {
        this.sqlSession = sqlSession;
    }
    @Override
    public List<User> getUsers() {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.getUsers();
    }
}

5.将上面的实现类注册到Spring中

• applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans 
    <!--引入外部配置文件-->
    <import resource="spring-dao.xml"/>
    <--注册mapper-->
    <bean id="userMapper" class="com.dong.mapper.UserMapperImpl">
        <property name="sqlSession" ref="sqlSession"/>
    </bean>
</beans>

6.测试

• MyTest.calss

public class MyTest {
    @Test
    public void test01(){
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserMapper userMapper = context.getBean("userMapper", UserMapper.class);
        for (User user:userMapper.getUsers()) {
            System.out.println(user);
        }
    }
}

8.2.2方式二(简化)

对比两种方式中的接口的实现类

• UserMapperImpl.calss

public class UserMapperImpl implements UserMapper{
    //在原来我们的所有操作都使用sqlSession来执行,现在都是使用SqlSessionTemplate
    private SqlSessionTemplate sqlSession;
    public void setSqlSession(SqlSessionTemplate sqlSession) {
        this.sqlSession = sqlSession;
    }
    @Override
    public List<User> getUsers() {
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.getUsers();
    }
}

• UserMapperImpl2.class

public class UserMapperImpl2 extends SqlSessionDaoSupport implements UserMapper{
    SqlSession sqlSession = getSqlSession();
    @Override
    public List<User> getUsers() {
        System.out.println("UserMapperImpl2");
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        return mapper.getUsers();
    }
}