mybatis-plus自动填充是如何匹配类属性createTime和字段名create_time

[阿旭。]

@Data
public class User {
    private Long id; //坑 不要把Long写成long了
    private String name;
    private Integer age;
    private String email;
    @TableField(fill = FieldFill.INSERT)
    private Date createTime;
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Date updateTime;
}

@Slf4j
@Component
public class CustomMetaObjectHandler implements MetaObjectHandler {
    @Override
    public void insertFill(MetaObject metaObject) {
        log.info("start insert fill....");
        this.setFieldValByName("createTime", new Date(), metaObject);
        this.setFieldValByName("updateTime", new Date(), metaObject);
    }

    @Override
    public void updateFill(MetaObject metaObject) {
        log.info("start update fill....");
        this.setFieldValByName("updateTime",new Date(),metaObject);
    }
}

   @Test
    public void testInsert(){
        User user = new User();
        user.setAge(18);
        user.setName("yx");
        user.setEmail("[e-mail]");
        int result = userMapper.insert(user);
        System.out.println("影响行数:"+result);
        System.out.println("id:"+user);
    }

Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@f2276c9] was not registered for synchronization because synchronization is not active
2020-12-26 15:51:32.964  INFO 8336 --- [           main] com.myd.handler.CustomMetaObjectHandler  : start insert fill....
2020-12-26 15:51:32.970  INFO 8336 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2020-12-26 15:51:33.159  INFO 8336 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
JDBC Connection [HikariProxyConnection@1343838143 wrapping com.mysql.cj.jdbc.ConnectionImpl@5d1d9d73] will not be managed by Spring
==>  Preparing: INSERT INTO user ( id, name, age, email, create_time, update_time ) VALUES ( ?, ?, ?, ?, ?, ? ) 
==> Parameters: 1342739812944273410(Long), yx(String), 18(Integer), [e-mail](String), 2020-12-26 15:51:32.964(Timestamp), 2020-12-26 15:51:32.964(Timestamp)
<==    Updates: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@f2276c9]
影响行数:1
id:User(id=1342739812944273410, name=yx, age=18, email=[e-mail], createTime=Sat Dec 26 15:51:32 CST 2020, updateTime=Sat Dec 26 15:51:32 CST 2020)
2020-12-26 15:51:33.226  INFO 8336 --- [extShutdownHook] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2020-12-26 15:51:33.232  INFO 8336 --- [extShutdownHook] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.

mybatis-plus 执行的插入语句中是怎么知道我的数据库里的字段是create_time，update_time的，又是怎么认定user类的createTime属性与数据库字段名create_time匹配？求大神解答

[viewgroup]

引用 1 楼 情非彼岸花 的回复:

驼峰命名规则，例如create_time 对应实体类字段就会匹配 createTime 同样的道理 createTime 将驼峰转为下划线的话 就是 create_time

一楼说的对，mybatis-plus 会将Java类的驼峰命名的属性与数据库中_命名的属性去匹配的。

[是赵敢敢啊]

把下划线的转换成驼峰的然后嗲用setter 赋值

[咦哟~~~]

驼峰命名规则，例如create_time 对应实体类字段就会匹配 createTime 同样的道理 createTime 将驼峰转为下划线的话 就是 create_time