mapper使用方法

分表存储，并且查询数据

<?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.questionnaire.study.mapper.DivOptingsContenMapper">    <resultMap id="BaseResultMap" type="com.questionnaire.study.pojo.DivOptingsConten">        <id column="num" property="num" jdbcType="INTEGER"/>        <result column="content" property="content" jdbcType="VARCHAR"/>        <result column="options" property="options" jdbcType="VARCHAR"/>        <result column="strength_index" property="strengthIndex" jdbcType="VARCHAR"/>        <result column="open_index" property="openIndex" jdbcType="VARCHAR"/>        <result column="title_number" property="titleNumber" jdbcType="INTEGER"/>        <collection property="divOptingsTitles" ofType="com.questionnaire.study.pojo.DivOptingsTitle">            <id column="id" property="id" jdbcType="INTEGER"/>            <result column="title_name" property="titleName" jdbcType="VARCHAR"/>            <result column="title_type" property="titleType" jdbcType="VARCHAR"/>            <result column="title_ describe" property="titleDescribe" jdbcType="VARCHAR"/>            <result column="title_num" property="titleNum" jdbcType="INTEGER"/>            <result column="titlt_mark" property="titltMark" jdbcType="VARCHAR"/>        </collection>    </resultMap>    <!-- 查询所有题库 -->    <select id="findAllQuestion" resultMap="BaseResultMap">        SELECT        `div_optings_conten`.`num`,        `div_optings_conten`.`content`,        `div_optings_conten`.`open_index`,        `div_optings_conten`.`strength_index`,        `div_optings_conten`.`title_number`,        `div_optings_title`.`title_ describe`,        `div_optings_title`.`title_name`,        `div_optings_title`.`title_num`,        `div_optings_title`.`title_type`,        `div_optings_title`.`titlt_mark`        from        `div_optings_conten`        LEFT JOIN `div_optings_title`        ON `div_optings_title`.`title_num` = `div_optings_conten`.`title_number`    </select>

实体

public class DivOptingsConten implements Serializable {    private Integer num;    private String content;    private String options;    private String strengthIndex;    private String openIndex;    private Integer titleNumber;    List<DivOptingsTitle> divOptingsTitles;

标题：

public class DivOptingsTitle implements Serializable {    private Integer id;    private String titleName;    private String titleType;    private String titleDescribe;    private Integer titleNum;    private String titltMark;