How to use Result Map in iBatis ?

The resultMap element is the most important and powerful in iBATIS.

It can reduce your iBatis code to minimum.

Example

EMPLOYEE table in MySQL

CREATE TABLE EMPLOYEE (

  id INT NOT NULL auto_increment,

  first_name VARCHAR(20) default NULL,

  last_name VARCHAR(20) default NULL,

  salary INT default NULL, PRIMARY KEY (id)

);

Employee POJO Class

public class Employee {

  private int id;

  private String first_name;

  private String last_name;

  private int salary;

  /* Getters and setters */

}

Employee.xml File

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN""http://ibatis.apache.org/dtd/sql-map-2.dtd">

<sqlMap namespace="Employee">

  <insert id="insert" parameterClass="Employee">

    insert into EMPLOYEE(first_name, last_name, salary) values (#first_name#, #last_name#, #salary#)

    <selectKey resultClass = "int" keyProperty="id">

        select last_insert_id() as id

     </selectKey>

  </insert>

  <select id="getAll" resultClass="Employee">

       SELECT * FROM EMPLOYEE

  </select>

  <update id="update" parameterClass="Employee">

      UPDATE EMPLOYEE SET first_name = #first_name# WHERE id = #id#

   </update>

   <delete id="delete" parameterClass="int">

      DELETE FROM EMPLOYEE WHERE id = #id#

   </delete>

   <!-- Using ResultMap -->

   <resultMap id="result" class="Employee">

    <result property="id" column="id"/>

    <result property="first_name" column="first_name"/>

    <result property="last_name" column="last_name"/>

    <result property="salary" column="salary"/>

   </resultMap>

   <select id="useResultMap" resultMap="result">

       SELECT * FROM EMPLOYEE WHERE id=#id#

    </select>

</sqlMap>

Java code to use Result Map

Reader rd = Resources.getResourceAsReader("SqlMapConfig.xml");

SqlMapClient smc = SqlMapClientBuilder.buildSqlMapClient(rd);

int id = 1;

System.out.println("Going to read record.....");

Employee e = (Employee) smc.queryForObject ("Employee.useResultMap", id);

System.out.println("ID: " + e.getId());

System.out.println("First Name: " + e.getFirstName());

System.out.println("Last Name: " + e.getLastName());

System.out.println("Salary: " + e.getSalary());

System.out.println("Record read Successfully ");