JavaWeb踩坑记录

org.apache.ibatis.binding.BindingException: Parameter 'XXXX' not found. 或 There is no getter for property named ‘XXX‘ in ‘class XXX

• 原因分析（首先这个问题在 Dao 层）
  1. 检查 SQL 语句，#{}中的内容是否存在拼写错误，或者与参数中@param注解中不一致的情况
  2. @param的使用错误，使用方法参考：MyBatis参数传递

Mapper method 'priv.dandelion.dao.BrandMapper.selectTotalCountByCondition attempted to return null from a method with a primitive return type (int).

• 原因分析：

  1. 是未配置 导致数据库与需要使用的名称不一致，需要配置@ResultMap使其名称一致就可以了

  2. 第二种情况就是误配置，如selectTotalCount 无返回值类型 就不要使用 @ResultMap，使用resultType，二者都不用会报错

     <select id="selectTotalCountByCondition" resultType="java.lang.Integer">
         select count(*) from tb_brand
         <where>
             <if test="brand.brandName != null and brand.brandName != ''">
                 brandName like #{brand.brandName}
             </if>
             <if test="brand.companyName != null and brand.companyName != ''">
                 and companyName like #{brand.companyName}
             </if>
             <if test="brand.status != null">
                 and status = #{brand.status}
             </if>
         </where>
     </select>
     

Unknown column 'companyName' in 'where clause'

• 原因分析：并没有按照resultMap进行解析，where 标签中的内容必须要和数据库中一致

  • 错误代码

    <!-- 条件查询 -->
    <select id="selectByPageAndCondition" resultMap="brandResultMap">
        select * from tb_brand
        <where>
            <if test="brand.brandName != null and brand.brandName != ''">
                brandName like #{brand.brandName}
            </if>
            <if test="brand.companyName != null and brand.companyName != ''">
                and companyName like #{brand.companyName}
            </if>
            <if test="brand.status != null">
                and status = #{brand.status}
            </if>
        </where>
        limit #{begin}, #{pageSize}
    </select>
    

  • 更整后代码

    <!-- 条件查询 -->
    <select id="selectByPageAndCondition" resultMap="brandResultMap">
        select * from tb_brand
        <where>
            <if test="brand.brandName != null and brand.brandName != ''">
                brand_name like #{brand.brandName}
            </if>
            <if test="brand.companyName != null and brand.companyName != ''">
                and company_name like #{brand.companyName}
            </if>
            <if test="brand.status != null">
                and status = #{brand.status}
            </if>
        </where>
        limit #{begin}, #{pageSize}
    </select>