MybatisPlus实现字段的自动填充

实现思路

• 利用Mybaits Plus中的@TableField的fill属性进行识别
• 自定义类实现MetaObjectHandler接口重写insertFill()和updateFill()

代码实现

• pom文件中引入MybatisPlus的依赖

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.5.2</version>
</dependency>

• 实体类中需要自动填充的属性通过@TableField的fill属性进行标注
• FieldFill为字段填充策略枚举类，定义了DEFAULT（默认不处理）、INSERT（插入时填充字段）、UPDATE（更新时填充字段）、INSERT_UPDATE（插入和更新时填充字段）等4种填充策略

@Data
@TableName(value = "scheme_config")
public class SchemeConfig {

    @TableId
    private Long phid;

    private Long schemeId;

    private Long subId;

    private String subType;

    private String businessNature;

    @TableField(fill = FieldFill.INSERT)
    private Date insertTime;

    @TableField(fill = FieldFill.INSERT)
    private Long createUser;

    @TableField(fill = FieldFill.UPDATE)
    private Date updateTime;

    @TableField(fill = FieldFill.UPDATE)
    private Long updateUser;
}

• 自定义填充器

/**
 * 自定义sql字段填充器，自动填充创建修改相关字段
 */
public class CustomMetaObjectHandler implements MetaObjectHandler {

    private static final String CREATE_USER = "createUser";

    private static final String INSERT_TIME = "insertTime";

    private static final String UPDATE_USER = "updateUser";

    private static final String UPDATE_TIME = "updateTime";

    @Override
    public void insertFill(MetaObject metaObject) {
        //为空则设置createUser
        Object createUser = metaObject.getValue(CREATE_USER);
        if(ObjectUtil.isNull(createUser)) {
            setFieldValByName(CREATE_USER, this.getUserUniqueId(), metaObject);
        }
        //为空则设置insertTime
        Object insertTime = metaObject.getValue(INSERT_TIME);
        if(ObjectUtil.isNull(insertTime)) {
            setFieldValByName(INSERT_TIME, new Date(), metaObject);
        }

    }

    @Override
    public void updateFill(MetaObject metaObject) {
        setFieldValByName(UPDATE_TIME, new Date(), metaObject);
        setFieldValByName(UPDATE_USER, this.getUserUniqueId(), metaObject);
    }

    /**
     * 获取用户唯一id
     */
    private Long getUserUniqueId() {
        return -1L;
        /*try {
            SysLoginUser sysLoginUser = LoginContextHolder.me().getSysLoginUserWithoutException();
            if(ObjectUtil.isNotNull(sysLoginUser)) {
                return sysLoginUser.getId();
            } else {
                return -1L;
            }
        } catch (Exception e) {
            //如果获取不到就返回-1
            return -1L;
        }*/
    }
}

• 装载自定义填充器

@Configuration
public class MybatisPlusConfig {

    /**
     * 自定义sql字段填充器
     */
    @Bean
    public CustomMetaObjectHandler metaObjectHandler(){
        return new CustomMetaObjectHandler();
    }
}

• 实现效果