Spring 5（四）：Spring整合MyBatis

快速上手

要和 Spring 一起使用 MyBatis，需要在 Spring 应用上下文中定义至少两样东西：

• 一个 SqlSessionFactory （可使用 SqlSessionFactoryBean 创建）
• 至少一个数据映射器类

在mybatis中，数据源和 SqlSessionFactory 都是用代码写的，在Spring中不用去new这个Factory，即工具类不用写了

---

1. 编写数据源
2. sqlSessionFactory
3. sqlSessionTemplate
4. 给接口加实现类
5. 将实现类注入到Spring
6. 测试使用

架构

• 配置文件

  • applicationContext.xml
  • mybatis-config.xml
  • spring-dao.xml

• 实体类

  • User

• mapper包

  • UserMapper
  • UserMapper.xml
  • UserMapperImpl

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"
       xmlns:context="http://www.springframework.org/schema/context"
       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/util http://www.springframework.org/schema/util/spring-util.xsd
                           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
                           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">

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

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

    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>

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

</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:context="http://www.springframework.org/schema/context"
       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/util http://www.springframework.org/schema/util/spring-util.xsd
                           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.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-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=GMT" />
        <property name="username" value="root" />
        <property name="password" value="1234" />
    </bean>

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

    <!--SqlSessionTemplate：就是我们使用的sqlSession-->
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <!--只能使用构造器注入sqlSessionFactory，因为没有set方法-->
        <constructor-arg index="0" ref="sqlSessionFactory" />
    </bean>

</beans>

User

public class User {
    private int id;
    private String name;
    private String password;

    public User() {
    }

    public User(int id, String name, String password) {
        this.id = id;
        this.name = name;
        this.password = password;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "User{" +
            "id=" + id +
            ", name='" + name + '\'' +
            ", password='" + password + '\'' +
            '}';
    }
}

UserMapper

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

UserMapper.xml

<mapper namespace="com.yue.mapper.UserMapper">
    <select id="getUserList" resultType="user">
        select * from user
    </select>
</mapper>

UserMapperImpl

public class UserMapperImpl implements UserMapper {

    //我们的所有操作，都使用sqlSession来执行，现在都使用sqlSessionTemplate
    private SqlSessionTemplate sqlSessionTemplate;

    public void setSqlSessionTemplate(SqlSessionTemplate sqlSessionTemplate) {
        this.sqlSessionTemplate = sqlSessionTemplate;
    }

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

}

测试

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

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

}

实现类的简化

继承 SqlSessionDaoSupport

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