问题描述

mapper.xml出现错误：Type handler was null on parameter mapping for property 'category'. It was either not specified and/or could not be found for the javaType (com.yykh.onemall.pojo.Category) : jdbcType (null) combination.

相关代码

mapper.xml:

<?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.yykh.onemall.mapper.ProductMapper">
 
    <resultMap id="Product"  type="com.yykh.onemall.pojo.Product">
        <id column="id" property="id"/>
        <result property="name" column="name"/>
        <result property="subTitle" column="subTitle"/>
        <result property="originalPrice" column="originalPrice"/>
        <result property="promotePrice" column="promotePrice"/>
        <result property="stock" column="stock"/>
        <result property="createDate" column="createDate"/>
        <association property="category"   javaType="com.yykh.onemall.pojo.Category">
            <id column="cid" property="id"/>
        </association>
    </resultMap>
 
    <select id="findOne" resultMap="Product">
      SELECT * from product where id =#{id}
    </select>
 
    <select id="findAll" resultMap="Product">
        select * from product where cid =#{id}
    </select>
 
</mapper>

pojo:

@Data
public class Product {
    int id;
    private Category category;
    private String name;
    private String subTitle;
    private float originalPrice;
    private float promotePrice;
    private int stock;
    private Date createDate;
}

mapper.interface:

public interface ProductMapper {
 
    @Insert("insert into product(name,subTitle,originalPrice,promotePrice,stock,createDate,category) values(#{name},#{subTitle},#{originalPrice},#{promotePrice},#{stock},#{createDate},#{category}) ")
    void save(Product bean);
 
    @Delete("delete from product where id =#{id}")
    void delete(int id);
 
 
    Product findOne(int id);
 
 
    Page<Product> findAll(Category category);
 
}