Use an implicit TypeHandler based on resultType for select in MyBatis

[Shobit Beltangdy]

Hi mybatis-users,

There's a question on StackOverflow that I came across related to implicitly using a custom typeHandler.  Since I am facing the same issue, I thought I should create a new topic and link the question below so that someone can respond to it (it's got a +50 reputation bounty ending in 7 days!)

http://stackoverflow.com/questions/30307031/use-an-implicit-typehandler-based-on-resulttype-for-select-in-mybatis

I'd appreciate your help.  Thanks.

[Ikchan Sim]

Used by <resultMap /> :

/* MyBatis Configuration XML File */

<typeHandlers>

    <typeHandler jdbcType="java.sql.Timestamp" javaType="org.joda.time.LocalDateTime" handler="...LocalDateTimeTypeHandler"/>

</typeHandlers>

/* Mapper Interface */

import org.joda.time.LocalDateTime;

public interface NotifMailDao {

    LocalDateTime getLastNotifTime();

}

/* MyBatis Mapper XML File */

<?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="lu.bgl.notif.mail.dao.NotifMailDao">

    <resultMap id="notifMailResultMap" type="org.joda.time.LocalDateTime">

        <result column="LAST_TIME" property="lastTime" jdbcType="java.sql.Timestamp" javaType="org.joda.time.LocalDateTime" />

    </resultMap>

    <select id="getLastNotifTime" resultMap="notifMailResultMap">

        SELECT current_timestamp AS LAST_TIME

        FROM   DUAL

    </select>

</mapper>

 

[Shobit Beltangdy]

Thanks Ikchan. However, this still does not answer OP's (and my) question.  What we were wondering is whether it is possible to achieve this without using a resultMap.

Just like how you can write a select like
<select id='someId' resultType='java.lang.String'> .... </select>

how can we implicitly do something like
<select id='someId' resultType='org.joda.time.DateTime'>...</select>

where we have a custom DateTimeTypeHandler having an annotation @JavaType=DateTime.class?

Is that possible, or is resultMap the only way to achieve this?

[Ikchan Sim]

Use the DateTypeHandler class jdbcType = "java.sql.Timestamp" type is implicitly bound to javaType = "java.util.Date".

If you want to use your Custom TypeHandler, you should use an explicit <resultMap />

@MappedTypes(value = DateTime.class)
@MappedJdbcTypes(value = { JdbcType.TIMESTAMP})
public class CustomTypeHandler extends BaseTypeHandler<byte[]> {
    // do something...
}

[Ikchan Sim]

Do not you look at the ResultSetHandler class it will help.