Mybatis逆向生成使用扩展类的实例代码详解

1.背景介绍

用的mybatis自动生成的插件，然而每次更改数据库的时候重新生成需要替换原有的mapper.xml文件，都要把之前业务相关的sql重新写一遍，感觉十分麻烦，就想着把自动生成的作为一个基础文件，然后业务相关的写在扩展文件里面，这样更改数据库后只需要把所有基础文件替换掉就可以了

2.代码

2.1 basemapper.java

把自动生成的方法都抽到一个base类，然后可以写一些公共的方法

/**
 * @author 吕梁山
 * @date 2019/4/23
 */
public interface basemapper<t> {
 int deletebyprimarykey(integer id);
 int insert(t entity);
 int insertselective(t entity);
 int updatebyprimarykeyselective(t entity);
 int updatebyprimarykey(t entity);
 t selectbyprimarykey(integer id);
}

2.2 usermapper.java

自动生成的mapper文件，里面基本都是空的了

public interface usermapper extends basemapper<user> { }

2.3 extusermapper.java

mapper的扩展类，业务相关的

/**
 * @author 吕梁山
 * @date 2019/4/25
 */
public interface extusermapper extends usermapper {

 extuser selectuserbyopenid(string openid);

 int existuserbyopenid(string openid);

 int updatebyopenid(user user);
}

2.4 usermapper.xml

自动生成的mapper.xml文件，没有改动，不同的生成器生成的可能不同

注意namespace要写正确

<?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.pikaqiu.barber.dao.base.usermapper">
 <resultmap id="baseresultmap" type="com.pikaqiu.barber.entity.base.user">
  <id column="id" property="id" jdbctype="integer"/>
  <result column="user_name" property="username" jdbctype="varchar"/>
  <result column="user_img" property="userimg" jdbctype="varchar"/>
  <result column="open_id" property="openid" jdbctype="varchar"/>
  <result column="phone" property="phone" jdbctype="varchar"/>
  <result column="sex" property="sex" jdbctype="integer"/>
  <result column="province" property="province" jdbctype="varchar"/>
  <result column="country" property="country" jdbctype="varchar"/>
  <result column="city" property="city" jdbctype="varchar"/>
  <result column="birth_date" property="birthdate" jdbctype="varchar"/>
  <result column="subscribe_date" property="subscribedate" jdbctype="timestamp"/>
  <result column="subscribe_scene" property="subscribescene" jdbctype="varchar"/>
  <result column="create_date" property="createdate" jdbctype="timestamp"/>
 </resultmap>
 <sql id="base_column_list">
  id, user_name, user_img, open_id, phone, sex, province, country, city, birth_date,
  subscribe_date, subscribe_scene, create_date
 </sql>
 <select id="selectbyprimarykey" resultmap="baseresultmap" parametertype="java.lang.integer">
  select
  <include refid="base_column_list"/>
  from t_user
  where id = #{id,jdbctype=integer}
 </select>
 <delete id="deletebyprimarykey" parametertype="java.lang.integer">
  delete from t_user
  where id = #{id,jdbctype=integer}
 </delete>
 <insert id="insert" parametertype="com.pikaqiu.barber.entity.base.user">
  insert into t_user (id, user_name, user_img,
       open_id, phone, sex,
       province, country, city,
       birth_date, subscribe_date, subscribe_scene,
       create_date)
  values (#{id,jdbctype=integer}, #{username,jdbctype=varchar}, #{userimg,jdbctype=varchar},
          #{openid,jdbctype=varchar}, #{phone,jdbctype=varchar}, #{sex,jdbctype=integer},
          #{province,jdbctype=varchar}, #{country,jdbctype=varchar},
          #{city,jdbctype=varchar},
          #{birthdate,jdbctype=varchar}, #{subscribedate,jdbctype=timestamp},
    #{subscribescene,jdbctype=varchar},
    #{createdate,jdbctype=timestamp})
 </insert>
 <insert id="insertselective" parametertype="com.pikaqiu.barber.entity.base.user">
  insert into t_user
  <trim prefix="(" suffix=")" suffixoverrides=",">
   <if test="id != null">
    id,
   </if>
   <if test="username != null">
    user_name,
   </if>
   <if test="userimg != null">
    user_img,
   </if>
   <if test="openid != null">
    open_id,
   </if>
   <if test="phone != null">
    phone,
   </if>
   <if test="sex != null">
    sex,
   </if>
   <if test="province != null">
    province,
   </if>
   <if test="country != null">
    country,
   </if>
   <if test="city != null">
    city,
   </if>
   <if test="birthdate != null">
    birth_date,
   </if>
   <if test="subscribedate != null">
    subscribe_date,
   </if>
   <if test="subscribescene != null">
    subscribe_scene,
   </if>
   <if test="createdate != null">
    create_date,
   </if>
  </trim>
  <trim prefix="values (" suffix=")" suffixoverrides=",">
   <if test="id != null">
    #{id,jdbctype=integer},
   </if>
   <if test="username != null">
    #{username,jdbctype=varchar},
   </if>
   <if test="userimg != null">
    #{userimg,jdbctype=varchar},
   </if>
   <if test="openid != null">
    #{openid,jdbctype=varchar},
   </if>
   <if test="phone != null">
    #{phone,jdbctype=varchar},
   </if>
   <if test="sex != null">
    #{sex,jdbctype=integer},
   </if>
   <if test="province != null">
    #{province,jdbctype=varchar},
   </if>
   <if test="country != null">
    #{country,jdbctype=varchar},
   </if>
   <if test="city != null">
    #{city,jdbctype=varchar},
   </if>
   <if test="birthdate != null">
    #{birthdate,jdbctype=varchar},
   </if>
   <if test="subscribedate != null">
    #{subscribedate,jdbctype=timestamp},
   </if>
   <if test="subscribescene != null">
    #{subscribescene,jdbctype=varchar},
   </if>
   <if test="createdate != null">
    #{createdate,jdbctype=timestamp},
   </if>
  </trim>
 </insert>
 <update id="updatebyprimarykeyselective" parametertype="com.pikaqiu.barber.entity.base.user">
  update t_user
  <set>
   <if test="username != null">
    user_name = #{username,jdbctype=varchar},
   </if>
   <if test="userimg != null">
    user_img = #{userimg,jdbctype=varchar},
   </if>
   <if test="openid != null">
    open_id = #{openid,jdbctype=varchar},
   </if>
   <if test="phone != null">
    phone = #{phone,jdbctype=varchar},
   </if>
   <if test="sex != null">
    sex = #{sex,jdbctype=integer},
   </if>
   <if test="province != null">
    province = #{province,jdbctype=varchar},
   </if>
   <if test="country != null">
    country = #{country,jdbctype=varchar},
   </if>
   <if test="city != null">
    city = #{city,jdbctype=varchar},
   </if>
   <if test="birthdate != null">
    birth_date = #{birthdate,jdbctype=varchar},
   </if>
   <if test="subscribedate != null">
    subscribe_date = #{subscribedate,jdbctype=timestamp},
   </if>
   <if test="subscribescene != null">
    subscribe_scene = #{subscribescene,jdbctype=varchar},
   </if>
   <if test="createdate != null">
    create_date = #{createdate,jdbctype=timestamp},
   </if>
  </set>
  where id = #{id,jdbctype=integer}
 </update>
 <update id="updatebyprimarykey" parametertype="com.pikaqiu.barber.entity.base.user">
  update t_user
  set user_name  = #{username,jdbctype=varchar},
   user_img  = #{userimg,jdbctype=varchar},
   open_id   = #{openid,jdbctype=varchar},
   phone   = #{phone,jdbctype=varchar},
   sex    = #{sex,jdbctype=integer},
   province  = #{province,jdbctype=varchar},
   country   = #{country,jdbctype=varchar},
   city   = #{city,jdbctype=varchar},
   birth_date  = #{birthdate,jdbctype=varchar},
   subscribe_date = #{subscribedate,jdbctype=timestamp},
   subscribe_scene = #{subscribescene,jdbctype=varchar},
   create_date  = #{createdate,jdbctype=timestamp}
  where id = #{id,jdbctype=integer}
 </update>
</mapper>

2.5 extusermapper.xml

业务相关的sql,这里用不了自动生成mapper.xml里面的baseresultmap这些东西

<?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.pikaqiu.barber.dao.extusermapper">
 <resultmap id="baseresultmap" type="com.pikaqiu.barber.entity.extuser">
  <id column="id" property="id" jdbctype="integer"/>
  <result column="user_name" property="username" jdbctype="varchar"/>
  <result column="user_img" property="userimg" jdbctype="varchar"/>
  <result column="open_id" property="openid" jdbctype="varchar"/>
  <result column="phone" property="phone" jdbctype="varchar"/>
  <result column="sex" property="sex" jdbctype="integer"/>
  <result column="province" property="province" jdbctype="varchar"/>
  <result column="country" property="country" jdbctype="varchar"/>
  <result column="city" property="city" jdbctype="varchar"/>
  <result column="birth_date" property="birthdate" jdbctype="varchar"/>
  <result column="subscribe_date" property="subscribedate" jdbctype="timestamp"/>
  <result column="subscribe_scene" property="subscribescene" jdbctype="varchar"/>
  <result column="create_date" property="createdate" jdbctype="timestamp"/>
 </resultmap>
 <update id="updatebyopenid" parametertype="com.pikaqiu.barber.entity.base.user" >
  update t_user
  <set>
   <if test="username != null">
    user_name = #{username,jdbctype=varchar},
   </if>
   <if test="userimg != null">
    user_img = #{userimg,jdbctype=varchar},
   </if>
   <if test="phone != null">
    phone = #{phone,jdbctype=varchar},
   </if>
   <if test="sex != null">
    sex = #{sex,jdbctype=integer},
   </if>
   <if test="province != null">
    province = #{province,jdbctype=varchar},
   </if>
   <if test="country != null">
    country = #{country,jdbctype=varchar},
   </if>
   <if test="city != null">
    city = #{city,jdbctype=varchar},
   </if>
   <if test="birthdate != null">
    birth_date = #{birthdate,jdbctype=varchar},
   </if>
   <if test="subscribedate != null">
    subscribe_date = #{subscribedate,jdbctype=timestamp},
   </if>
   <if test="subscribescene != null">
    subscribe_scene = #{subscribescene,jdbctype=varchar},
   </if>
   <if test="createdate != null">
    create_date = #{createdate,jdbctype=timestamp},
   </if>
  </set>
  where open_id = #{openid,jdbctype=integer}
 </update>
 <select id="selectuserbyopenid" parametertype="string" resultmap="baseresultmap">
  select *
  from t_user
  where open_id = #{openid,jdbctype=varchar}
 </select>

 <select id="existuserbyopenid" parametertype="string" resulttype="integer">
  select count(0)
  from t_user
  where open_id = #{openid,jdbctype=varchar}
 </select>
</mapper>

2.6 userserviceimpl.java

service层调用的时候直接调用扩展的mapper

/**
 * @author 吕梁山
 * @date 2019/4/23
 */
@service("userservice")
public class userserviceimpl implements userservice {

 @resource
 private extusermapper extusermapper;

 @override
 public extuser getuserbyopenid(string openid) {
  return extusermapper.selectuserbyopenid(openid);
 }
}

注：如果生成的mapper.xml和extmapper.xml不在同一个目录，需要在application.yml将所有mapper.xml文件都添加到扫描中

mybatis:
 #扫描sql.xml文件
 mapper-locations: classpath:mapping/**/*.xml
 #自动扫描实体类
 type-aliases-package: com.pikaqiu.barber.entity

至此，每次更改数据库结构后，直接重新生成文件对base文件进行替换即可，不需要再去将业务代码复制重新粘贴

总结

以上所述是小编给大家介绍的mybatis逆向生成使用扩展类的实例代码详解,希望对大家有所帮助