Using resultmap of mybatis to collect objects into a linkedhashmap

[Ajay Bodhe]

I have two tables: employee_details(department_id, employee_id) & skill_details(employee_id, skill_id). I want to construct LinkedHashMap<Employee_Details> for each department_id, such that class Employee_Details { long employee_id; ArrayList<long> skill_ids; // other data & code may be ----; ----; } That means each employee_id for that department_id will result in new Employee_Details object which will be pushed into LinkedHashMap<Employee_Details>. And all skills for the same employee_id will be stored into Arraylist<long> skill_ids field in Employee_Details. How this can be achieved using resultmaps in mybatis?

[Guy Rouillier]

Take a look in the MyBatis User's Guide. You can do everything you are
trying to do, *except* for having MyBatis return a LinkedHashMap. You
can ask it to return a Map, but you can't specify the specific
implementation. If you really insist on LinkedHashMap, you can create
one by wrapping the returned Map in a LinkedHashMap constructor.

On 9/9/2014 3:15 PM, Ajay Bodhe wrote:
>
> <http://stackoverflow.com/questions/25751906/using-resultmap-of-mybatis-to-collect-objects-into-a-linkedhashmap#>

>
>
>
> I have two tables: employee_details(department_id, employee_id) &
> skill_details(employee_id, skill_id). I want to construct
> LinkedHashMap<Employee_Details> for each department_id, such that
>
> |class Employee_Details {
> long employee_id;
> ArrayList<long> skill_ids;
> // other data & code may be
> ----;
> ----;
> }
>

> That means each/employee_id/ for that/department_id/ will result in new/Employee_Details/ object which will be
> pushed into/LinkedHashMap<Employee_Details>/. And all skills for the same/employee_id/ will be stored into/
> Arraylist<long> skill_ids/ field in/Employee_Details/.

>
> |How this can be achieved using resultmaps in mybatis?
>
>

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[Ajay Bodhe]

Hi Guy,
I went through http://mybatis.github.io/mybatis-3/sqlmap-xml.html#Result_Maps
this to get an idea of association n collection in resultmap
I am coding first time in java & mybatis, so if possible some help/xml-java-code-snippet would be great.
Thanks,
Ajay

> <mailto:mybatis-user+unsub...@googlegroups.com>.

[Eduardo Macarron]

I would say that you can specify a LinkedHashMap as a resultType in xml or as a return type for a mapper method. 

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[Eduardo Macarron]

Just out of curiosity, I tested it and it works. See:

https://github.com/mybatis/mybatis-3/commit/84580150118e59e6dfc6b930b6add2c5f21f333b

[Ajay Bodhe]

thnx got it

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[Ajay Bodhe]

HI Eduardo,

How can you specify the return type as java.util.LinkedHashMap with resultMao?
I need to specify the return type as Employee_Details right?
with that I am getting following error:
                 java.lang.ClassCastException: java.util.HashMap cannot be cast to java.util.LinkedHashMap



/*******************************mysql query*****************************/
<select id="getEmployeeIDSkillIDMapping" resultMap="EmployeeIDSkillIDMapper">
             SELECT employeeID, skillID from employee_skillset;
</select>

/*******************************resultMap*****************************/
    <resultMap id="EmployeeIDSkillIDMapper" type="com.Employee_Details">
             <id property="employeeID" column="employeeID"/>
             <collection property="skillIDs" javaType="java.util.ArrayList" column="employeeID" ofType="long">
                 <result column="skillID"/>
             </collection>
</resultMap>

/*******************************interface*****************************/
@MapKey("employeeID")
    public LinkedHashMap<Long, Employee_Details> getEmployeeIDSkillIDMapping();

/*******************************class definition*****************************/

class Employee_Details {
    Long employeeID;
    ArrayList<Long> skillIDs;

    // other data & code may be
    ----;
    ----; 
}

/*******************************pom.xml*****************************/
<dependency>

	<groupId>org.mybatis</groupId>

	<artifactId>mybatis-guice</artifactId>

	<version>3.3</version>

</dependency>

LET ME KNOW WHAT MISTAKEs I AM DOING.

Thanks

On Wednesday, 10 September 2014 22:07:40 UTC+5:30, Eduardo wrote:

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