Mybatis

Mybatis将sql和其他java代码分开，只需要将sql写在usermap里

流程：不做session.commit 就会进行回滚

1)配置mybatis-config.xml 全局配置文件 (1.数据源 2.外部的mapper)
2）构建sqlSessionFactory
3）通过sqlSessionFactory构建SqlSession对象
4）通过Sqlsession操作数据库CRUD
5）调用Session.commit提交事务
6）调用Session.close关闭会话

mybatis自动生成UserMapper.xml配置文件：首先build-加generator

参考：https://blog.csdn.net/a656678879/article/details/80469191           

修改generator.xml时，project structure-libraries可以找到数据库驱动安装的位置

最终的UserMapper.xml的增删改查

<?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可以随便起-->
<!--<mapper namespace="main.java.com.mapper.UserMapper" >-->
<mapper namespace="dao.UserDao" >
  <resultMap id="userMap" type="pojo.User" >
    <!--
      WARNING - @mbggenerated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    <id column="id" property="id" jdbcType="BIGINT" />
    <result column="name" property="name" jdbcType="VARCHAR" />
    <result column="qq" property="qq" jdbcType="VARCHAR" />
    <result column="type" property="type" jdbcType="INTEGER" />
    <result column="time" property="time" jdbcType="BIGINT" />
    <result column="link" property="link" jdbcType="VARCHAR" />
    <result column="create_at" property="createAt" jdbcType="BIGINT" />
    <result column="create_by" property="createBy" jdbcType="BIGINT" />
    <result column="update_at" property="updateAt" jdbcType="BIGINT" />
    <result column="update_by" property="updateBy" jdbcType="BIGINT" />
  </resultMap>
  <sql id="common" >
    <!--
      WARNING - @mbggenerated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    id, name, qq, type, time, link, create_at, create_by, update_at, update_by
  </sql>

  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Long" >
    <!--
      WARNING - @mbggenerated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    select 
    <include refid="common" />
    from user
    where id = #{id,jdbcType=BIGINT}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Long" >
    <!--
      WARNING - @mbggenerated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    delete from user
    where id = #{id,jdbcType=BIGINT}
  </delete>
  <insert id="addUser" parameterType="pojo.User"  useGeneratedKeys="true" keyProperty="id">
    <!--
      WARNING - @mbggenerated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    insert into user (name, qq,
      type, time, link, create_at, 
      create_by, update_at, update_by
      )
    values ( #{name,jdbcType=VARCHAR}, #{qq,jdbcType=VARCHAR},
      #{type,jdbcType=INTEGER}, #{time,jdbcType=BIGINT}, #{link,jdbcType=VARCHAR}, #{createAt,jdbcType=BIGINT}, 
      #{createBy,jdbcType=BIGINT}, #{updateAt,jdbcType=BIGINT}, #{updateBy,jdbcType=BIGINT}
      )
  </insert>
  <insert id="insertSelective" parameterType="pojo.User" >
    <!--
      WARNING - @mbggenerated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    insert into user
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        id,
      </if>
      <if test="name != null" >
        name,
      </if>
      <if test="qq != null" >
        qq,
      </if>
      <if test="type != null" >
        type,
      </if>
      <if test="time != null" >
        time,
      </if>
      <if test="link != null" >
        link,
      </if>
      <if test="createAt != null" >
        create_at,
      </if>
      <if test="createBy != null" >
        create_by,
      </if>
      <if test="updateAt != null" >
        update_at,
      </if>
      <if test="updateBy != null" >
        update_by,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        #{id,jdbcType=BIGINT},
      </if>
      <if test="name != null" >
        #{name,jdbcType=VARCHAR},
      </if>
      <if test="qq != null" >
        #{qq,jdbcType=VARCHAR},
      </if>
      <if test="type != null" >
        #{type,jdbcType=INTEGER},
      </if>
      <if test="time != null" >
        #{time,jdbcType=BIGINT},
      </if>
      <if test="link != null" >
        #{link,jdbcType=VARCHAR},
      </if>
      <if test="createAt != null" >
        #{createAt,jdbcType=BIGINT},
      </if>
      <if test="createBy != null" >
        #{createBy,jdbcType=BIGINT},
      </if>
      <if test="updateAt != null" >
        #{updateAt,jdbcType=BIGINT},
      </if>
      <if test="updateBy != null" >
        #{updateBy,jdbcType=BIGINT},
      </if>
    </trim>
  </insert>
  <update id="updateUser" parameterType="pojo.User" >
    <!--
      WARNING - @mbggenerated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    update user
    <set >
      <if test="name != null" >
        name = #{name,jdbcType=VARCHAR},
      </if>
      <if test="qq != null" >
        qq = #{qq,jdbcType=VARCHAR},
      </if>
      <if test="type != null" >
        type = #{type,jdbcType=INTEGER},
      </if>
      <if test="time != null" >
        time = #{time,jdbcType=BIGINT},
      </if>
      <if test="link != null" >
        link = #{link,jdbcType=VARCHAR},
      </if>
      <if test="createAt != null" >
        create_at = #{createAt,jdbcType=BIGINT},
      </if>
      <if test="createBy != null" >
        create_by = #{createBy,jdbcType=BIGINT},
      </if>
      <if test="updateAt != null" >
        update_at = #{updateAt,jdbcType=BIGINT},
      </if>
      <if test="updateBy != null" >
        update_by = #{updateBy,jdbcType=BIGINT},
      </if>
    </set>
    where id = #{id,jdbcType=BIGINT}
  </update>
  <update id="updateByPrimaryKey" parameterType="pojo.User" >
    <!--
      WARNING - @mbggenerated
      This element is automatically generated by MyBatis Generator, do not modify.
    -->
    update user
    set name = #{name,jdbcType=VARCHAR},
      qq = #{qq,jdbcType=VARCHAR},
      type = #{type,jdbcType=INTEGER},
      time = #{time,jdbcType=BIGINT},
      link = #{link,jdbcType=VARCHAR},
      create_at = #{createAt,jdbcType=BIGINT},
      create_by = #{createBy,jdbcType=BIGINT},
      update_at = #{updateAt,jdbcType=BIGINT},
      update_by = #{updateBy,jdbcType=BIGINT}
    where id = #{id,jdbcType=BIGINT}
  </update>

  <select id="selectObject" resultMap="pojo.User">
    select * from user
    where id = {#id}
  </select>

  <select id="selectList" resultMap="pojo.User">
    select <include refid="common"/> from user
  </select>

</mapper>

把数据库中的列定义成java代码中的属性，可以进行驼峰映射

<result column="create_at" property="createAt" jdbcType="BIGINT" />

将mybatis-config存为模板文件

下一次日报内容：

sqlSession

UserImpl + UserDao+UserDaoTest