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MyBatis-generator的使用

King's Studio

MyBatis-generator的使用

MyBatis

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 2019/10/05   Share

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MyBatis生成器（MBG）是MyBatis和iBATIS的代码生成器。它为MyBatis的所有版本以及iBATIS生成代码。它将一个数据库表（或多个表），生成可用于访问表的组件。这减轻了设置对象和配置文件与数据库表进行交互的麻烦。MBG试图对简单CRUD（创建，检索，更新，删除）的大部分数据库操作进行简化。但开发者仍将需要手工编写SQL语句和对象代码以进行联接查询或存储过程。MyBatis-generator是由MyBatis官方提供的技术，现在网上有很多利用Maven导入的MyBatis-generator插件使用的教程，在此我想对操作进行一些简化，直接利用mybatis-generator-core的jar包进行操作，方便演示整个执行的过程。

搭建Mysql数据库的环境

首先在你的数据库中创建一张用户表，使用MyBatis-generator帮我们自动创建entity类、mapper文件以及dao接口并且帮我们配置好它们的依赖关系。

create table  t_user
(
       user_id           int primary key auto_increment	/*用户id*/,
       user_email        VARCHAR(50) 	/*邮箱*/,
       user_name         VARCHAR(50) 	/*昵称*/,
       user_pwd          VARCHAR(50) 	/*密码*/,
       user_sex          VARCHAR(50) 	/*性别*/,
       user_city         VARCHAR(50) 	/*所在城市*/,
       user_avatar       VARCHAR(50) 	/*头像*/,
       user_motto        VARCHAR(50) 	/*个性签名*/,
       user_money        int	/*账户余额*/,
       user_status       int 	/*用户状态 1:正常2:禁用*/,
       userCreate_time   DATE 	/*用户创建时间 默认为当前时间*/
);

MyBatis-generator最核心的配置在于generatorConfig.xml文件的配置，此文件用于规定我们连接的是哪一个数据库，哪一张表，以及生成的策略是什么。

<!--首先在mybatis-generator-core核心jar包的同级目录下加入数据库连接的jar包，指定连接jar包的位置-->
<classPathEntry location="mysql-connector-java-5.1.18-bin.jar" />

然后是数据库连接信息的配置，同样oracle的连接也需要加入对应的ojdbc的jar包以及修改连接信息。

<!--mysql的连接信息-->
<jdbcConnection driverClass="com.mysql.jdbc.Driver"
        						connectionURL="jdbc:mysql://129.204.207.233:3306/qa"
        						userId="root"
        						password="xxxxxx">
</jdbcConnection>

附上完整的generatorConfig.xml配置。

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
  PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
  "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>
	<!-- 数据库驱动:选择你的本地硬盘上面的数据库驱动包 -->
	<classPathEntry location="mysql-connector-java-5.1.18-bin.jar" />

  <context id="mysql" targetRuntime="MyBatis3">
		<plugin type="org.mybatis.generator.plugins.RowBoundsPlugin"></plugin>
		<plugin type="org.mybatis.generator.plugins.SerializablePlugin"></plugin>  
    <plugin type="org.mybatis.generator.plugins.MapperConfigPlugin">
      <property name="targetPackage" value="."/>
      <property name="targetProject" value="src"/>
    </plugin>

	<commentGenerator>
		<property name="suppressAllComments" value="true" />
	</commentGenerator>
  <!--mysql的连接信息-->
  <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                  connectionURL="jdbc:mysql://129.204.207.233:3306/qa"
                  userId="root"
                  password="xxxxxx">
  </jdbcConnection>

  <javaTypeResolver >
      <property name="forceBigDecimals" value="false" />
  </javaTypeResolver>
	<!--生成实体类的位置-->
  <javaModelGenerator targetPackage="entity" targetProject="src">
      <property name="enableSubPackages" value="true" />
      <property name="trimStrings" value="true" />
  </javaModelGenerator>
	<!--生成Mapperxml的位置-->
  <sqlMapGenerator targetPackage="mapper"  targetProject="src">
      <property name="enableSubPackages" value="true" />
  </sqlMapGenerator>
	<!--生成dao接口的位置-->
  <javaClientGenerator type="XMLMAPPER" targetPackage="dao"  targetProject="src">
      <property name="enableSubPackages" value="true" />
  </javaClientGenerator>

	<table schema="ums" tableName="t_user" domainObjectName="User">
		<!-- 忽略外键的列，不配置则直接生成id，而不是对象，对象需要自己手动添加 -->
		<!-- <ignoreColumn column="class_id"></ignoreColumn> -->
  </table>
	
  </context>
</generatorConfiguration>

执行java -jar命令生成代码

需要在mybatis-generator-core-1.3.2.jar的同级目录下执行该命令，然后Mybatis-generator会根据配置好的generatorConfig.xml生成对应的代码。

java -jar mybatis-generator-core-1.3.2.jar -configfile generatorConfig.xml -overwrite

如果生成成功，会有下面的提示。

MyBatis Generator finished successfully.

整个测试项目的结构

生成代码目录的结构：

实际开发中，我们通常会使用MyBatis-generator为我们配置好表和实体类的对应关系，而生成的Mapper.xml完全符合开发的代码规范，它已经帮我们做好了resultMap的配置，示例如下：

<?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="dao.UserMapper" >
  <resultMap id="BaseResultMap" type="entity.User" >
    <id column="user_id" property="userId" jdbcType="INTEGER" />
    <result column="user_email" property="userEmail" jdbcType="VARCHAR" />
    <result column="user_name" property="userName" jdbcType="VARCHAR" />
    <result column="user_pwd" property="userPwd" jdbcType="VARCHAR" />
    <result column="user_sex" property="userSex" jdbcType="VARCHAR" />
    <result column="user_city" property="userCity" jdbcType="VARCHAR" />
    <result column="user_avatar" property="userAvatar" jdbcType="VARCHAR" />
    <result column="user_motto" property="userMotto" jdbcType="VARCHAR" />
    <result column="user_money" property="userMoney" jdbcType="INTEGER" />
    <result column="user_status" property="userStatus" jdbcType="INTEGER" />
    <result column="userCreate_time" property="usercreateTime" jdbcType="DATE" />
  </resultMap>
  <sql id="Example_Where_Clause" >
    <where >
      <foreach collection="oredCriteria" item="criteria" separator="or" >
        <if test="criteria.valid" >
          <trim prefix="(" suffix=")" prefixOverrides="and" >
            <foreach collection="criteria.criteria" item="criterion" >
              <choose >
                <when test="criterion.noValue" >
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue" >
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue" >
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue" >
                  and ${criterion.condition}
                  <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Update_By_Example_Where_Clause" >
    <where >
      <foreach collection="example.oredCriteria" item="criteria" separator="or" >
        <if test="criteria.valid" >
          <trim prefix="(" suffix=")" prefixOverrides="and" >
            <foreach collection="criteria.criteria" item="criterion" >
              <choose >
                <when test="criterion.noValue" >
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue" >
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue" >
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue" >
                  and ${criterion.condition}
                  <foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Base_Column_List" >
    user_id, user_email, user_name, user_pwd, user_sex, user_city, user_avatar, user_motto, 
    user_money, user_status, userCreate_time
  </sql>
  <select id="selectByExample" resultMap="BaseResultMap" parameterType="entity.UserExample" >
    select
    <if test="distinct" >
      distinct
    </if>
    <include refid="Base_Column_List" />
    from t_user
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
    <if test="orderByClause != null" >
      order by ${orderByClause}
    </if>
  </select>
  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    select 
    <include refid="Base_Column_List" />
    from t_user
    where user_id = #{userId,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    delete from t_user
    where user_id = #{userId,jdbcType=INTEGER}
  </delete>
  <delete id="deleteByExample" parameterType="entity.UserExample" >
    delete from t_user
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
  </delete>
  <insert id="insert" parameterType="entity.User" >
    insert into t_user (user_id, user_email, user_name, 
      user_pwd, user_sex, user_city, 
      user_avatar, user_motto, user_money, 
      user_status, userCreate_time)
    values (#{userId,jdbcType=INTEGER}, #{userEmail,jdbcType=VARCHAR}, #{userName,jdbcType=VARCHAR}, 
      #{userPwd,jdbcType=VARCHAR}, #{userSex,jdbcType=VARCHAR}, #{userCity,jdbcType=VARCHAR}, 
      #{userAvatar,jdbcType=VARCHAR}, #{userMotto,jdbcType=VARCHAR}, #{userMoney,jdbcType=INTEGER}, 
      #{userStatus,jdbcType=INTEGER}, #{usercreateTime,jdbcType=DATE})
  </insert>
  <insert id="insertSelective" parameterType="entity.User" >
    insert into t_user
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="userId != null" >
        user_id,
      </if>
      <if test="userEmail != null" >
        user_email,
      </if>
      <if test="userName != null" >
        user_name,
      </if>
      <if test="userPwd != null" >
        user_pwd,
      </if>
      <if test="userSex != null" >
        user_sex,
      </if>
      <if test="userCity != null" >
        user_city,
      </if>
      <if test="userAvatar != null" >
        user_avatar,
      </if>
      <if test="userMotto != null" >
        user_motto,
      </if>
      <if test="userMoney != null" >
        user_money,
      </if>
      <if test="userStatus != null" >
        user_status,
      </if>
      <if test="usercreateTime != null" >
        userCreate_time,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="userId != null" >
        #{userId,jdbcType=INTEGER},
      </if>
      <if test="userEmail != null" >
        #{userEmail,jdbcType=VARCHAR},
      </if>
      <if test="userName != null" >
        #{userName,jdbcType=VARCHAR},
      </if>
      <if test="userPwd != null" >
        #{userPwd,jdbcType=VARCHAR},
      </if>
      <if test="userSex != null" >
        #{userSex,jdbcType=VARCHAR},
      </if>
      <if test="userCity != null" >
        #{userCity,jdbcType=VARCHAR},
      </if>
      <if test="userAvatar != null" >
        #{userAvatar,jdbcType=VARCHAR},
      </if>
      <if test="userMotto != null" >
        #{userMotto,jdbcType=VARCHAR},
      </if>
      <if test="userMoney != null" >
        #{userMoney,jdbcType=INTEGER},
      </if>
      <if test="userStatus != null" >
        #{userStatus,jdbcType=INTEGER},
      </if>
      <if test="usercreateTime != null" >
        #{usercreateTime,jdbcType=DATE},
      </if>
    </trim>
  </insert>
  <select id="countByExample" parameterType="entity.UserExample" resultType="java.lang.Integer" >
    select count(*) from t_user
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
  </select>
  <update id="updateByExampleSelective" parameterType="map" >
    update t_user
    <set >
      <if test="record.userId != null" >
        user_id = #{record.userId,jdbcType=INTEGER},
      </if>
      <if test="record.userEmail != null" >
        user_email = #{record.userEmail,jdbcType=VARCHAR},
      </if>
      <if test="record.userName != null" >
        user_name = #{record.userName,jdbcType=VARCHAR},
      </if>
      <if test="record.userPwd != null" >
        user_pwd = #{record.userPwd,jdbcType=VARCHAR},
      </if>
      <if test="record.userSex != null" >
        user_sex = #{record.userSex,jdbcType=VARCHAR},
      </if>
      <if test="record.userCity != null" >
        user_city = #{record.userCity,jdbcType=VARCHAR},
      </if>
      <if test="record.userAvatar != null" >
        user_avatar = #{record.userAvatar,jdbcType=VARCHAR},
      </if>
      <if test="record.userMotto != null" >
        user_motto = #{record.userMotto,jdbcType=VARCHAR},
      </if>
      <if test="record.userMoney != null" >
        user_money = #{record.userMoney,jdbcType=INTEGER},
      </if>
      <if test="record.userStatus != null" >
        user_status = #{record.userStatus,jdbcType=INTEGER},
      </if>
      <if test="record.usercreateTime != null" >
        userCreate_time = #{record.usercreateTime,jdbcType=DATE},
      </if>
    </set>
    <if test="_parameter != null" >
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByExample" parameterType="map" >
    update t_user
    set user_id = #{record.userId,jdbcType=INTEGER},
      user_email = #{record.userEmail,jdbcType=VARCHAR},
      user_name = #{record.userName,jdbcType=VARCHAR},
      user_pwd = #{record.userPwd,jdbcType=VARCHAR},
      user_sex = #{record.userSex,jdbcType=VARCHAR},
      user_city = #{record.userCity,jdbcType=VARCHAR},
      user_avatar = #{record.userAvatar,jdbcType=VARCHAR},
      user_motto = #{record.userMotto,jdbcType=VARCHAR},
      user_money = #{record.userMoney,jdbcType=INTEGER},
      user_status = #{record.userStatus,jdbcType=INTEGER},
      userCreate_time = #{record.usercreateTime,jdbcType=DATE}
    <if test="_parameter != null" >
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByPrimaryKeySelective" parameterType="entity.User" >
    update t_user
    <set >
      <if test="userEmail != null" >
        user_email = #{userEmail,jdbcType=VARCHAR},
      </if>
      <if test="userName != null" >
        user_name = #{userName,jdbcType=VARCHAR},
      </if>
      <if test="userPwd != null" >
        user_pwd = #{userPwd,jdbcType=VARCHAR},
      </if>
      <if test="userSex != null" >
        user_sex = #{userSex,jdbcType=VARCHAR},
      </if>
      <if test="userCity != null" >
        user_city = #{userCity,jdbcType=VARCHAR},
      </if>
      <if test="userAvatar != null" >
        user_avatar = #{userAvatar,jdbcType=VARCHAR},
      </if>
      <if test="userMotto != null" >
        user_motto = #{userMotto,jdbcType=VARCHAR},
      </if>
      <if test="userMoney != null" >
        user_money = #{userMoney,jdbcType=INTEGER},
      </if>
      <if test="userStatus != null" >
        user_status = #{userStatus,jdbcType=INTEGER},
      </if>
      <if test="usercreateTime != null" >
        userCreate_time = #{usercreateTime,jdbcType=DATE},
      </if>
    </set>
    where user_id = #{userId,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="entity.User" >
    update t_user
    set user_email = #{userEmail,jdbcType=VARCHAR},
      user_name = #{userName,jdbcType=VARCHAR},
      user_pwd = #{userPwd,jdbcType=VARCHAR},
      user_sex = #{userSex,jdbcType=VARCHAR},
      user_city = #{userCity,jdbcType=VARCHAR},
      user_avatar = #{userAvatar,jdbcType=VARCHAR},
      user_motto = #{userMotto,jdbcType=VARCHAR},
      user_money = #{userMoney,jdbcType=INTEGER},
      user_status = #{userStatus,jdbcType=INTEGER},
      userCreate_time = #{usercreateTime,jdbcType=DATE}
    where user_id = #{userId,jdbcType=INTEGER}
  </update>
  <select resultMap="BaseResultMap" parameterType="entity.UserExample" id="selectByExampleWithRowbounds" >
    select
    <if test="distinct" >
      distinct
    </if>
    <include refid="Base_Column_List" />
    from t_user
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    </if>
    <if test="orderByClause != null" >
      order by ${orderByClause}
    </if>
  </select>
</mapper>

原文作者：金奇

原文链接：https://www.rossontheway.com/2019/10/05/MyBatis-generator的使用/

发表日期：October 5th 2019, 12:00:00 am

更新日期：October 5th 2019, 12:10:45 pm

版权声明：本文采用知识共享署名-非商业性使用 4.0 国际许可协议进行许可，除特别声明外，转载请注明出处！

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1. 1. 搭建Mysql数据库的环境
2. 2. 执行java -jar命令生成代码
3. 3. 整个测试项目的结构

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缺失模块。
1、请确保node版本大于6.2
2、在博客根目录（注意不是archer根目录）执行以下命令：
npm i hexo-generator-json-content --save
3、在根目录_config.yml里添加配置：

jsonContent:
  meta: false
  pages: false
  posts:
    title: true
    date: true
    path: true
    text: false
    raw: false
    content: false
    slug: false
    updated: false
    comments: false
    link: false
    permalink: false
    excerpt: false
    categories: true
    tags: true

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