Mybatis环境配置

一、导入依赖

在pom.xml导入Mybatis 和Mysql的相关依赖。

代码如下：

        <!-- Mybatis核心-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.9</version>
        </dependency>

        <!-- junit测试-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>

        <!-- Mysql驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.28</version>
        </dependency>

 

二、核心配置文件

mybatis-config.xml是Mybatis的核心配置文件。

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>
    <!--配置连接数据库的环境-->
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
                <property name="username" value="root"/>
                <property name="password" value="529529"/>
            </dataSource>
        </environment>
    </environments>
    <!--引入映射文件-->
    <mappers>
        <mapper resource="mappers/UserMapper.xml"/>
    </mappers>
</configuration>

 

三、映射文件

创建SQL映射的xml文件。

UserMapper.xml：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ang.Mapper.UserMapper">
    <!--查询用户-->
    <select id="findUserById" parameterType="int" resultType="com.ang.demo1.User">
        select *
        from t_user
        where id = #{id}
    </select>
</mapper>

 

四、测试类

public class TestMybatis {
    private SqlSessionFactory sqlSessionFactory;
    private SqlSession sqlSession;

    @Before
    public void init() {
        //加载核心配置文件
        try (InputStream is = Resources.getResourceAsStream("mybatis-config.xml")) {
            //获取SqlSessionFactoryBuilder
            SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
            //获取SqlSessionFactory
            sqlSessionFactory = sqlSessionFactoryBuilder.build(is);
            //获取SqlSession
            sqlSession = sqlSessionFactory.openSession();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Test
    public void testUser() {
        //查找
        User user2 = sqlSession.selectOne("findUserById",3);
        System.out.println(user2.toString());
    }

    @After
    public void destroy() {
        //提交事务
        sqlSession.commit();
        //关闭sqlSession
        sqlSession.close();
    }
}