MyBatis: How to return a map of lists?

Question

I have Googled this until I was blue in the face and could not find an answer. How can I configure MyBatis to return a Map of Lists ?

ie

HashMap<String, List<Foo>>

For example, if I had a query that returned all the orders for all my customers and I wanted to get it to return a Map containing a list of the orders keyed by the customer id.

EDIT

I found a way to do it by writing a custom ResultHandler, but would rather have MyBatis do it for me much like Hibernate does with either mapping or annotations.

Thanks.

Answer 1

The easiest thing I have found was creating a new POJO and putting the id and list of objects in there.

StringFoo.java

public class StringFoo {
    String name;
    List<Foo> foos;
}

Mapper.java

List<StringFoo> findFoo(@Param("id") Long id);

Mapper.xml

<resultMap id="FooResultMap" type="com.package.StringFoo">
    <result property="name" column="name"/>
    <collection property="foo" resultMap="FooMapORJavaType"/>
</resultMap>
<select id="findFoo" resultMap="FooResultMap"></select>