ResultMapping

Use either <resultMap> or <entity> to map query results:

<resultMap>: map SQL result sets.
<entity>: map a concrete table.

How to choose between resultMap and entity?

For the same table with different query shapes, entity is good when columns all come from one table; resultMap when columns span multiple tables.
Using the Fluent API requires entity or object-mapping annotations.
If the SELECT uses aliases, functions, CASE, or columns from multiple tables, resultMap is safer.

##resultMap tag

using resultMap
<resultMap id="user_resultMap" type="com.example.dto.UserBean">
    <result column="id" property="id"/>
    <result column="name" property="name"/>
    <result column="age" property="age"/>
    <result column="create_time" property="createTime"/>
</resultMap>

<select id="queryById" resultMap="user_resultMap">
    select
        id, name, age, create_time
    from
        users
    where
        id = #{id}
</select>

Attributes

resultMap tag

Property	Description
id	可选 Identifier; if empty, `type` is used.
type	必选 Fully qualified Java type to map to.
caseInsensitive	可选 Case-insensitive mapping for column/property names. Default `true`.
autoMapping	可选 Whether to perform auto-mapping. Default `true`.
mapUnderscoreToCamelCase	可选 With auto-mapping, convert camelCase property names to snake_case columns (e.g., `createTime` → `create_time`). Default `false`.

result tag

Property	Description
column	必选 Column name in the result set.
property	必选 Property name in the target type.
javaType	可选 Usually inferred; specify when the property is abstract or an interface.
jdbcType	可选 Overrides the default Java↔JDBC mapping.
typeHandler	可选 Override the type handler to use.

Attributes​

Attributes