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{ 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{ }
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
<&＃63;xml version="1.0" encoding="UTF-8" &＃63;>id, user_name, user_img, open_id, phone, sex, province, country, city, birth_date, subscribe_date, subscribe_scene, create_date delete from t_user where id = #{id,jdbcType=INTEGER} 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 into t_user id, user_name, user_img, open_id, phone, sex, province, country, city, birth_date, subscribe_date, subscribe_scene, create_date, #{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}, update t_user where id = #{id,jdbcType=INTEGER} 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}, 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}
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
<&＃63;xml version="1.0" encoding="UTF-8" &＃63;>update t_user where open_id = #{openId,jdbcType=INTEGER} user_name = #{userName,jdbcType=VARCHAR}, user_img = #{userImg,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},
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，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！
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