[JAVA] Moved from iBATIS to MyBatis3

I finally migrated my old system built with Spring + iBATIS to Spring + MyBatis3. I have tried migrating several times, but the number of SQL definition files exceeds 1000, and it takes too much time to manually migrate to the definition file for MyBatis. Official? tool did not work well, so I gave up. However, if I couldn't migrate to MyBatis, I couldn't upgrade Spring, so I thought it was awkward, so I created a definition file migration tool and completed the migration safely. I don't think there is much demand, but I decided to make it public so that it would be of some help to those who are in trouble somewhere.

I couldn't migrate successfully with the official tools

Mybatis / ibatis2mybatis on GitHub seems to be the official tool, but I decided to make a migration tool because this tool could not migrate successfully in the following cases did. (I think there were others, but I forgot ...)

• Use the <dynamic>, <isPropertyAvailable>, <isNotPropertyAvailable> tags
• When the property attribute is undefined in tags such as<isEqual>,<isNotEqual>,<iterate>

Migration work

Library changes

• Change Gradle settings to use MyBatis library

Change before

compile group: 'org.apache.ibatis', name: 'ibatis-sqlmap', version: '2.3.4.726'

After change

compile group: 'org.mybatis', name: 'mybatis', version: '3.4.5'
compile group: 'org.mybatis', name: 'mybatis-spring', version: '1.3.1'

Change settings

• Change from SqlMapClientFactoryBean to use SqlSessionFactoryBean.
• In iBATIS, when mapping the result obtained by the SELECT statement to the Map object, it was also mapped even if it was null. However, MyBatis does not map if it is null by default, so change the setting (callSettersOnNulls) to make it behave the same.
• In iBATIS, rows with null results are also mapped and empty instances are returned. However, MyBatis is supposed to return null, so change the setting (returnInstanceForEmptyRow) to get the same behavior. However, this change will also return empty instances when mapping nested results. In this case, iBATIS returned null, so in order to make it the same behavior, the migration tool described later sets notNullColumn.

Change before

<bean id="sqlMapClient" class="org.springframework.orm.ibatis.SqlMapClientFactoryBean" scope="singleton">
  <property name="configLocations">
    <list>
       <value>classpath:/ibatis.xml</value>
    </list>
  </property>
  <property name="dataSource" ref="dataSource" />
</bean>

After change

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
  <property name="dataSource" ref="dataSource" />
  <property name="mapperLocations" value="classpath*:/mybatis/**/*.xml" />
  <property name="configuration">
    <bean class="org.apache.ibatis.session.Configuration">
      <property name="callSettersOnNulls" value="true"/>
      <property name="returnInstanceForEmptyRow" value="true"/>
    </bean>
  </property>
</bean>

Code changes

• Change the inheritance source from SqlMapClientDaoSupport to SqlSessionDaoSupport
• Change getSqlMapClient () to getSqlSession ()
• Change getSqlMapClient (). QueryForObject () to getSqlSession (). SelectOne ()
• Change getSqlMapClient (). QueryForList () to getSqlSession (). SelectList ()

Change before

public class Dao extends SqlMapClientDaoSupport {
    public Object find(String id) throws SQLException {
        return getSqlMapClient().queryForObject(id);
    }
    public List findList(String id) throws SQLException {
        return getSqlMapClient().queryForList(id);
    }
}

After change

public class Dao extends SqlSessionDaoSupport {
    public Object find(String id) throws SQLException {
        return getSqlSession().selectOne(id);
    }
    public List findList(String id) throws SQLException {
        return getSqlSession().selectList(id);
    }
}

Migrate sqlMap file to mapper file

I have created a tool for migrating iBATIS sqlMap files to MyBatis mapper files, so I will use it. You will need the JDK to run this tool, so please install it in advance.

GitHub - ogasada/ibatisToMyBatis3

1. Get the project from GitHub $ git clone https://github.com/ogasada/ibatisToMyBatis3.git
2. Modify the configuration file and specify the directory where the source sqlMap file is stored.

• Specify the full path of the storage directory in systemProp.targetDir in the gradle.properties file

3. Run the program and migrate to the mapper file $ ./gradlew convert

• The migration program overwrites the sqlMap file with the mapper file. Therefore, a backup is automatically created when the program is executed. Create the backup directory in the same location as the directory specified in the configuration file.

The migration tool may be inadequate as I limit it to the features I need. The program itself is not a big deal, so I think you can add functions if you change it appropriately.