MyBatis-Plus 中 typeHandler 的使用实例详解
作者：小裕哥略帅
本文介绍了在MyBatis-Plus中如何使用typeHandler处理json格式字段和自定义typeHandler,通过使用JacksonTypeHandler,可以简单实现将实体类字段转换为json格式存储,感兴趣的朋友跟随小编一起看看吧
一、typeHandler 的使用
1、存储json格式字段
如果字段需要存储为json格式，可以使用JacksonTypeHandler处理器。使用方式非常简单，如下所示：
在domain实体类里面要加上，两个注解
@TableName(autoResultMap = true) 表示自动映射resultMap
@TableField(typeHandler = JacksonTypeHandler.class)表示将UserInfo对象转为json对象入库
/**
* 物料分类
*/
@TableField(typeHandler = SupplierMaterialCategoryTypeHandler.class)
private List<MaterialCategory> materialCategory;2、自定义 typeHandler 实现类
例如当我们 某个字段存储的类型为List或者Map时，我们可以自定义一个TypeHandler，以 list 为例，我们想存储一个字段类型为 list ,在数据库中的存储的格式是 多条数据以逗号分割，当查询时会自动根据逗号分割成列表格式。
需要实现BaseTypeHandler抽象类：
package com.mdgyl.hussar.basic.handler;
import com.mdgyl.common.util.vo.ChangeInfoVO;
import com.mdgyl.data.mybatis.plus.typehandler.ListTypeHandler;
import com.mdgyl.hussar.basic.supplier.masterdata.domain.SupplierDO;
/**
* @author shuquanlin
*/
public class SupplierMaterialCategoryTypeHandler extends ListTypeHandler<SupplierDO.MaterialCategory> {
@Override
protected SupplierDO.MaterialCategory specificType() {
return new SupplierDO.MaterialCategory();
}
}在mybaits中的xml文件中
<?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.mdgyl.hussar.basic.supplier.changeorder.dao.ChangeOrderMapper">
<resultMap id="BaseResultMap" type="com.mdgyl.hussar.basic.supplier.changeorder.domain.SupplierChangeOrderDo">
<id column="id" property="id" jdbcType="BIGINT" />
<result column="tenant_id" property="tenantId" jdbcType="BIGINT" />
<result column="supplier_id" property="supplierId" jdbcType="BIGINT" />
<result column="code" property="code" jdbcType="BIGINT" />
<result column="els_account" property="elsAccount" jdbcType="VARCHAR" />
<result column="name" property="name" jdbcType="VARCHAR" />
<result column="external_code" property="externalCode" jdbcType="VARCHAR" />
<result column="material_category" property="materialCategory" typeHandler="com.mdgyl.hussar.basic.handler.ChangeOrderMaterialCategoryTypeHandler" />
<result column="status" property="status" jdbcType="VARCHAR" />
<result column="audit_status" property="auditStatus" jdbcType="VARCHAR" />
<result column="source_scene" property="sourceScene" jdbcType="VARCHAR" />
<result column="score" property="score" jdbcType="DECIMAL" />
<result column="contact_information" property="contactInformation" jdbcType="VARCHAR" />
<result column="inquiry_type" property="inquiryType" jdbcType="VARCHAR" />
<result column="route" property="route" jdbcType="VARCHAR" />
<result column="transaction_currency" property="transactionCurrency" jdbcType="VARCHAR" />
<result column="payment_currency" property="paymentCurrency" jdbcType="VARCHAR" />
<result column="payment_condition" property="paymentCondition" jdbcType="VARCHAR" />
<result column="open_account_condition" property="openAccountCondition" jdbcType="VARCHAR" />
<result column="operating_start_time" property="operatingStartTime" jdbcType="DATE" />
<result column="taxpayer_identity_number" property="taxpayerIdentityNumber" jdbcType="VARCHAR" />
<result column="unified_social_credit_code" property="unifiedSocialCreditCode" jdbcType="VARCHAR" />
<result column="belong_company_id" property="belongCompanyId" jdbcType="BIGINT" />
<result column="purchaser_head_id" property="purchaserHeadId" jdbcType="BIGINT" />
<result column="create_user_id" property="createUserId" jdbcType="BIGINT" />
<result column="create_user_name" property="createUserName" jdbcType="VARCHAR" />
<result column="update_user_id" property="updateUserId" jdbcType="BIGINT" />
<result column="update_user_name" property="updateUserName" jdbcType="VARCHAR" />
<result column="update_time" property="updateTime" jdbcType="TIMESTAMP" />
<result column="create_time" property="createTime" jdbcType="TIMESTAMP" />
<result column="delete_flag" property="deleteFlag" jdbcType="VARCHAR" />
<result column="legal_representative" property="legalRepresentative" jdbcType="VARCHAR" />
<result column="supplier_data_id" property="supplierDataId" jdbcType="BIGINT" />
</resultMap>
<select id="groupByStatus" parameterType="com.mdgyl.hussar.basic.param.changeOrder.SupplierChangeOrderPageQueryParam" resultType="com.mdgyl.hussar.basic.model.common.StatusGroupModel">
SELECT status AS status,
count(id) AS count
FROM `t_supplier_change_order`
WHERE tenant_id = #{tenantId} AND delete_flag = '0'
<if test="code != null and code != ''">
AND code = #[code]
</if>
<if test="elsAccount != null and elsAccount != ''">
AND els_account = #{elsAccount}
</if>
<if test="name != null and name != ''">
AND name = #{name}
</if>
<if test="supplierId != null and supplierId != ''">
AND supplier_id = #{supplierId}
</if>
GROUP BY status
</select>
</mapper>
如果要查找json中的字段，可以在domain类里面加上虚拟字段
@TableField(exist = false)
public static final String materialCategoryUserIdQuery = "JSON_CONTAINS(material_category, JSON_OBJECT('materialCategoryUserId', {0}))";在xml文件中加上
<if test="name != null and name != ''">
AND JSON_CONTAINS(material_category, JSON_OBJECT('materialCategoryName', #{name}))
</if>到此这篇关于MyBatis-Plus 之 typeHandler 的使用的文章就介绍到这了,更多相关MyBatis-Plus typeHandler 使用内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！