MyBatis映射配置文件

映射配置文件介绍

<?xml version="1.0" encoding="UTF-8" ?>
<!--MyBatis的DTD约束-->
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!--
    mapper 核心的根标签
    namespces属性：名称空间
-->
<mapper namespace="StudentMapper">

    <!--
   select 查询功能的标签
   id属性：唯一标识
   resultType属性:指定结果映射对象类型
   paramenterType属性:指定才是映射对象类型
-->
    <select id="selectAll" resultType="com.itheima.bean.Student">
        select * from student
    </select>
</mapper>

查询功能

 @Test
    public void selectAll() throws IOException {
        /// 加载核心配置文件
        InputStream inputStream =Resources.getResourceAsStream("MyBatisConfig.xml");
        // 获取sqlSession工程对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        /// t通过工程对象获取sqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();

        /// 执行映射配置文件中的sql语句，并接收结果
        List<Student> selectList = sqlSession.selectList("StudentMapper.selectAll");

        /// 处理结果
        for (Student student:selectList)
        {
            System.out.println(student);
        }

        /// 释放资源
        sqlSession.close();
        inputStream.close();

    }

    @Test
    public void selectById() throws Exception {
        /*
            根据ID查询
         */

        /// 加载核心配置文件
        InputStream inputStream= Resources.getResourceAsStream("MyBatisConfig.xml");
        /// 获取SqlSession工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        /// 通过工程对象获取SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        ///执行映射配置文件中的sql语句，并接受结果
        Student student = sqlSession.selectOne("StudentMapper.selectById", 3);
        /// 处理结果
        System.out.println(student);

        sqlSession.close();
        inputStream.close();

    }

<?xml version="1.0" encoding="UTF-8" ?>
<!--MyBatis的DTD约束-->
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!--
    mapper 核心的根标签
    namespces属性：名称空间
-->
<mapper namespace="StudentMapper">

    <!--
   select 查询功能的标签
   id属性：唯一标识
   resultType属性:指定结果映射对象类型
   paramenterType属性:指定才是映射对象类型
-->
    <select id="selectAll" resultType="com.itheima.bean.Student">
        select * from student
    </select>
    <select id="selectById" resultType="com.itheima.bean.Student" parameterType="java.lang.Integer">
        select * from student where id = #{id}
    </select>
</mapper>

新增功能

 @Test
    public void insert() throws IOException {
        /// 新增功能

        /// 加载核心配置文件
        InputStream inputStream= Resources.getResourceAsStream("MyBatisConfig.xml");
        /// 获取SqlSession工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        /// 通过工程对象获取SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        ///执行映射配置文件中的sql语句，并接受结果
        Student student = new Student(4,"赵六",26);
        int result = sqlSession.insert("StudentMapper.insert",student);

        /// 提交事务
        sqlSession.commit();
        /// 处理结果
        System.out.println(result);

        sqlSession.close();
        inputStream.close();
    }

<?xml version="1.0" encoding="UTF-8" ?>
<!--MyBatis的DTD约束-->
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!--
    mapper 核心的根标签
    namespces属性：名称空间
-->
<mapper namespace="StudentMapper">

    <!--
   select 查询功能的标签
   id属性：唯一标识
   resultType属性:指定结果映射对象类型
   paramenterType属性:指定才是映射对象类型
-->
    <select id="selectAll" resultType="com.itheima.bean.Student">
        select * from student
    </select>
    <select id="selectById" resultType="com.itheima.bean.Student" parameterType="java.lang.Integer">
        select * from student where id = #{id}
    </select>
    <insert id="insert" parameterType="com.itheima.bean.Student">
        insert into student values(#{id},#{name},#{age})
    </insert>
</mapper>

修改操作

   @Test
    public void update() throws IOException {
        /// 修改功能

        /// 加载核心配置文件
        InputStream inputStream= Resources.getResourceAsStream("MyBatisConfig.xml");
        /// 获取SqlSession工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        /// 通过工程对象获取SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        ///执行映射配置文件中的sql语句，并接受结果
        Student student = new Student(4,"赵六",37);
        int result = sqlSession.update("StudentMapper.update",student);

        /// 提交事务
        sqlSession.commit();
        /// 处理结果
        System.out.println(result);

        sqlSession.close();
        inputStream.close();
    }

<?xml version="1.0" encoding="UTF-8" ?>
<!--MyBatis的DTD约束-->
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!--
    mapper 核心的根标签
    namespces属性：名称空间
-->

```xml
<mapper namespace="StudentMapper">

    <!--
   select 查询功能的标签
   id属性：唯一标识
   resultType属性:指定结果映射对象类型
   paramenterType属性:指定才是映射对象类型
-->
    <select id="selectAll" resultType="com.itheima.bean.Student">
        select * from student
    </select>
    <select id="selectById" resultType="com.itheima.bean.Student" parameterType="java.lang.Integer">
        select * from student where id = #{id}
    </select>
    <insert id="insert" parameterType="com.itheima.bean.Student">
        insert into student values(#{id},#{name},#{age})
    </insert>
    <update id="update" parameterType="com.itheima.bean.Student">
        update student set name =#{name},age=#{age} where id =#{id}
    </update>
</mapper>

```删除功能

@Test
    public void delete() throws IOException {
        /// 删除功能

        /// 加载核心配置文件
        InputStream inputStream= Resources.getResourceAsStream("MyBatisConfig.xml");
        /// 获取SqlSession工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        /// 通过工程对象获取SqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        ///执行映射配置文件中的sql语句，并接受结果
      
        int result = sqlSession.delete("StudentMapper.delete",4);

        /// 提交事务
        sqlSession.commit();
        /// 处理结果
        System.out.println(result);

        sqlSession.close();
        inputStream.close();
    }

<?xml version="1.0" encoding="UTF-8" ?>
<!--MyBatis的DTD约束-->
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!--
    mapper 核心的根标签
    namespces属性：名称空间
-->
<mapper namespace="StudentMapper">

    <!--
   select 查询功能的标签
   id属性：唯一标识
   resultType属性:指定结果映射对象类型
   paramenterType属性:指定才是映射对象类型
-->
    <select id="selectAll" resultType="com.itheima.bean.Student">
        select * from student
    </select>
    <select id="selectById" resultType="com.itheima.bean.Student" parameterType="java.lang.Integer">
        select * from student where id = #{id}
    </select>
    <insert id="insert" parameterType="com.itheima.bean.Student">
        insert into student values(#{id},#{name},#{age})
    </insert>
    <update id="update" parameterType="com.itheima.bean.Student">
        update student set name =#{name},age=#{age} where id =#{id}
    </update>
    <delete id="delete" parameterType="java.lang.Integer">
        delete from student where id =#{id}
    </delete>
</mapper>

小结