Specify the jdbcType as blob
<resultMap id="kpDataMap" type="KPData">
<id property="kpId" jdbcType="INTEGER" column="KPID" />
<result property="fName" jdbcType="VARCHAR" column="FNAME" />
<result property="lName" jdbcType="VARCHAR" column="LNAME" />
<result property="salary" jdbcType="BIGINT" column="SALARY"/>
<result property="img" jdbcType="BLOB" column="IMG" />
</resultMap>
<insert id="setKPData" parameterType="KPData">
INSERT INTO KPDATA(KPID,FNAME,LNAME,SALARY,IMG)
VALUES(#{kpId},#{fName},#{lName},#{salary, javaType=java.math.BigInteger, jdbcType=BIGINT},#{img, jdbcType=BLOB})
</insert>
<select id="getKPData" resultMap="kpDataMap">
SELECT KPID,FNAME,LNAME,SALARY,IMG
FROM KPDATA
WHERE KPID=#{kpId}
</select>
public class KPData {
private int kpId;
private String fName;
private String lName;
private BigInteger salary;
private byte[] img;
//getters and setters
}