ibatis遷移mybatis詳細方案(含指令碼和注意事項)
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ibatis已成過去式,官方早已不再維護,使用ibatis的老應用遷移到mybatis很有必要,且好用的服務層框架springboot集成了mybatis,支援維護良好,更加說明了遷移到mybatis的重要性,下面詳細說明整個遷移流程
1.使用 ibatis到mybatis的map檔案轉換工具
轉換工具:ibatis2mybatis
可以幫你將ibatis 2.x sqlmap檔案轉換為myBatis 3.x mapper檔案,該工具是使用了Ant構建任務進行XSTL轉換和一些語法文字替換
該工具下載下來使用非常簡單,把你要轉換的所有sqlmap檔案放到source資料夾,然後在當前目錄直接執行ant命令即可,轉換成功的mapper檔案放在了destination資料夾下。不過遺憾的是,ant命令並不總是執行成功,跟你的sqlmap檔案有關,比如我當時轉換時報錯如下:
BUILD FAILED
/Users/zhumin/Documents/ibatis2mybatis-ibatis2mybatis-1.0/build.xml:24: javax.xml.transform.TransformerException: javax.xml.transform.TransformerException: com.sun.org.apache.xml.internal.utils.WrappedRuntimeException: unknown protocol: classpath
at com.sun.org.apache.xalan.internal.xsltc .trax.TransformerImpl.transform(TransformerImpl.java:749)
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:351)
at org.apache.tools.ant.taskdefs.optional.TraXLiaison.transform(TraXLiaison.java:197)
at org.apache.tools.ant.taskdefs.XSLTProcess.process(XSLTProcess.java :844)
at org.apache.tools.ant.taskdefs.XSLTProcess.execute(XSLTProcess.java:434)
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:293)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
at org.apache.tools.ant.Task.perform(Task.java:348)
at org.apache.tools.ant.Target.execute(Target.java:435)
at org.apache.tools.ant.Target.performTasks(Target.java:456)
at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1405)
at org.apache.tools.ant.Project.executeTarget(Project.java:1376)
at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
at org.apache.tools.ant.Project.executeTargets(Project.java:1260)
at org.apache.tools.ant.Main.runBuild(Main.java:854)
at org.apache.tools.ant.Main.startAnt(Main.java:236)
at org.apache.tools.ant.launch.Launcher.run(Launcher.java:285)
at org.apache.tools.ant.launch.Launcher.main(Launcher.java:112)
Caused by: javax.xml.transform.TransformerException: com.sun.org.apache.xml.internal.utils.WrappedRuntimeException: unknown protocol: classpath
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getDOM(TransformerImpl.java:578)
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:739)
... 21 more
Caused by: com.sun.org.apache.xml.internal.utils.WrappedRuntimeException: unknown protocol: classpath
at com.sun.org.apache.xalan.internal.xsltc.dom.XSLTCDTMManager.getDTM(XSLTCDTMManager.java:427)
at com.sun.org.apache.xalan.internal.xsltc.dom.XSLTCDTMManager.getDTM(XSLTCDTMManager.java:215)
at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getDOM(TransformerImpl.java:556)
... 22 more
看到unknown protocol: classpath
錯誤時發現是我的sqlmap DTD檔案找不到,我的sqlmap一開始是這樣的:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN" "classpath:com/ibatis/sqlmap/engine/builder/xml/sql-map-2.dtd" >
<sqlMap namespace="funUser">
...
</sqlMap>
其中DTDs直接引用的jar包裡的檔案,工具無法識別就會報錯,只能將其去掉,然後就轉換成功了
2. 自己寫指令碼修復轉換後mapper檔案裡的錯誤
不要以為一個工具就完事了,它只是試圖在複雜的工作開始之前提供一個良好的起點,減少一點轉換成本
轉換後的mapper檔案可能仍有一堆無法轉換的部分或者轉換錯誤,以我的應用為例,當時轉換完成後有下面幾個問題:
無法識別ibatis中jdbcType的型別
很多sqlmap檔案寫了resultMap,而且還加了jdbcType,比如:
<resultMap id="resultMap" type="user">
<result property="id" column="id" jdbcType="BIGINT"/>
<result property="appName" column="app_name" jdbcType="VARCHAR"/>
<result property="displayName" column="display_name" jdbcType="VARCHAR"/>
<result property="avatar" column="avatar" jdbcType="VARCHAR"/>
<result property="userId" column="user_id" jdbcType="BIGINT"/>
<result property="gmtCreate" column="gmt_create" jdbcType="DATETIME"/>
<result property="gmtModified" column="gmt_modified" jdbcType="DATETIME"/>
</resultMap>
轉換工具保持原樣,而mybatis的jdbcType已經換了型別關鍵詞,不再是BIGINT啊這些,最好方法就是去掉,一個檔案就有這麼多的欄位要改,20個檔案豈不是要手動改幾百次,當然用指令碼了:
sed -i '' 's/ jdbcType.*\/\>/\/\>/g' ./*.xml
注意:mybatis有兩種欄位對映的方式:select別名和resultmap方式,詳細可看:mybatis – MyBatis 3 | Mapper XML 檔案
需要遷移\元素
轉換後的mapper檔案去掉了無法轉換的\元素,因為mybatis裡<typeAlias>
必須從<sqlMap>
元素移動到 <configuration><typeAliases>...</typeAliases></configuration>
這個裡面,需要手動加個mybatis-config.xml
檔案:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<typeAliases>
<typeAlias alias="app" type="com.tmall.wireless.fun.core.app.AppDO" />
...
<typeAlias alias="punish" type="com.tmall.wireless.fun.core.punish.PunishDO"/>
</typeAliases>
</configuration>
個別動態標籤需要手動加上
雖然上面工具能轉換大部分動態sql比如<isNotNull>
和<iterate>
,但像<isNotEmpty>
這樣的動態sql是不支援的,需要手動轉換
檢查一下具體的sql語句有沒有轉換錯誤
該工具還是比較強大的,可以將你的動態sql轉換成功,比如<isNotNull.*?property=\"(.*?)\"></isNotNull>
改為:<if test="$1 != null"></if>
,<iterate>
標籤改為<foreach>
標籤,但免不了可能存在連線符丟失的情況,比如我有一條sql轉換後少了一個and
3. sql DAO類的改動
ibatis使用spring封裝好的SqlMapClientTemplate進行DAO類的增刪改查,我們只需要繼承SpringFramework中提供的SqlMapClientDaoSupport類即可
/**
* 把sql map client 注進來
*
* @author 竹敏 2016.3.25
*/
@SuppressWarnings("deprecation")
public class AutowiringSqlMapClientDaoSupport extends SqlMapClientDaoSupport {
@Resource
public void injectSqlMapClient(SqlMapClient sqlMapClient) {
super.setSqlMapClient(sqlMapClient);
}
}
然後通過getSqlMapClientTemplate()
即可進行select/insert/update/delete
操作
public class AppDAO extends AutowiringSqlMapClientDaoSupport {
public AppDO selectAppByName(String appName) {
return (AppDO) getSqlMapClientTemplate().queryForObject(
"funApp.selectByName", appName);
}
...
}
而mybatis採用的是SqlSessionTemplate進行操作,上面的類就要改成:
public class AppDAO {
@Resource
private SqlSessionTemplate sqlSessionTemplate;
public AppDO selectAppByName(String appName) {
return (AppDO) sqlSessionTemplate.selectOne("funApp.selectByName", appName);
}
...
}
想想如果有20個檔案(大工程遠不止),每個檔案都要如此改,和完全重寫工作量差不多,有兩種方案可改善:
採用介面卡模式
很簡單,就是寫個適配原來ibatis的DAO操作,介面如下:
/**
* Created by jinshuan.li on 2016/8/15.
* 適配ibatis的sqlmaptemplete
*/
public interface SqlMapClientAdapter {
SqlSession getSqlSession();
int insert(String statement, Object params);
<T> T queryForObject(String statement, Object params);
int update(String statement, Object params);
<T> List<T> queryForList(String statement, Object params);
<T> List<T> queryForList(String statement);
void delete(String statement, Object params);
<T> T queryForObject(String statement);
}
在介面卡的實現類中呼叫SqlSession的相關方法:
**
* Created by jinshuan.li on 2016/8/15.
*/
@Repository("sqlSessionMapClient")
public class SqlSessionMapClient implements SqlMapClientAdapter {
@Resource(name = "sqlSessionTemplate")
private SqlSession sqlSession;
@Override
public SqlSession getSqlSession() {
return sqlSession;
}
@Override
public int insert(String statement, Object params) {
return sqlSession.insert(statement, params);
}
@Override
public <T> T queryForObject(String statement, Object params) {
return sqlSession.selectOne(statement, params);
}
@Override
public int update(String statement, Object params) {
return sqlSession.update(statement, params);
}
@Override
public <T> List<T> queryForList(String statement, Object params) {
return sqlSession.selectList(statement, params);
}
@Override
public <T> List<T> queryForList(String statement) {
return sqlSession.selectList(statement);
}
@Override
public void delete(String statement, Object params) {
sqlSession.delete(statement, params);
}
@Override
public <T> T queryForObject(String statement) {
return sqlSession.selectOne(statement);
}
}
直接指令碼批量改
介面卡方式在大多數情況下都是優選方案,值得推薦,但免不了仍到處到是ibatis的影子,強迫症患者可能不想忍,要改就改徹底了,絕不留下ibatis的影子,那怎麼辦尼?只能手動寫指令碼批量改了,熟悉指令碼的人很快就能寫好,每個人都需要根據自己程式碼情況進行定製指令碼,比如我的如下:
#### ibatis2mybatis_dao.sh
# 把getSqlMapClientTemplate()改成sqlSessionTemplate
find . -name "*DAO\.java" | xargs perl -pi -e 's|getSqlMapClientTemplate\(\)|sqlSessionTemplate|g'
# 方法名稱一一對應改掉,queryForObject——>selectOne,queryForList——>selectList
find . -name "*DAO\.java" | xargs perl -pi -e 's|queryForObject|selectOne|g'
find . -name "*DAO\.java" | xargs perl -pi -e 's|queryForList|selectList|g'
find . -name "*DAO\.java" | xargs perl -pi -e 's|return[\s]*sqlSessionTemplate [\s]*\.selectList|return sqlSessionTemplate\.selectList|g'
# 去掉不再使用的AutowiringSqlMapClientDaoSupport輔助類
find . -name "*DAO\.java" | xargs perl -pi -e 's|import com\.tmall\.wireless\.fun\.core\.utils\.AutowiringSqlMapClientDaoSupport;||g'
find . -name "*DAO\.java" | xargs perl -pi -e 's| extends AutowiringSqlMapClientDaoSupport||g'
find . -name "*DAO\.java" | xargs sed -i '' '/@SuppressWarnings/d'
# 新增新的SqlSessionTemplate注入
find . -name "*DAO\.java" | xargs sed -i '' '/public class/a\
@Resource'
find . -name "*DAO\.java" | xargs sed -i '' '/@Resource/G'
find . -name "*DAO\.java" | xargs sed -i '' '/@Resource/a\
private SqlSessionTemplate sqlSessionTemplate;'
find . -name "*DAO\.java" | xargs sed -i '' '/public class/G'
find . -name "*DAO\.java" | xargs sed -i '' 's/^@Resource/ @Resource/'
find . -name "*DAO\.java" | xargs sed -i '' 's/^private/ private^/'
還有一些微調的部分,不適合用指令碼,比如mybatis的insert方法已經不再返回新的id了,而是需要我們呼叫成功後直接從物件引數裡獲取,這裡可能需要手動調整下
4. 資料來源配置變更
上面說了ibatis使用的是SqlMapClientTemplate物件,dataSource配置如下:
<?xml version="1.0" encoding="UTF-8" ?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
"
default-autowire="byName">
<tx:annotation-driven transaction-manager="transactionManager"/>
<bean id="dataSource" class="com.taobao.tddl.jdbc.group.TGroupDataSource" init-method="init">
<property name="appName" value="TMALL_FUN_APP" />
<property name="dbGroupKey" value="TMALL_FUN_GROUP" />
</bean>
<bean id="sqlMapClient" class="org.springframework.orm.ibatis.SqlMapClientFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="configLocations">
<list>
<value>classpath*:dao/sqlMapConfig.xml</value>
</list>
</property>
</bean>
<bean id="sqlMapClientTemplate" class="org.springframework.orm.ibatis.SqlMapClientTemplate">
<property name="sqlMapClient" ref="sqlMapClient" />
</bean>
<bean id="transactionManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource" />
</bean>
</beans>
而mybatis使用的是SqlSessionTemplate,資料來源需要改動配置:
<?xml version="1.0" encoding="UTF-8" ?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd
"
default-autowire="byName">
<tx:annotation-driven transaction-manager="transactionManager"/>
<bean id="dataSource" class="com.taobao.tddl.jdbc.group.TGroupDataSource" init-method="init">
<property name="appName" value="TMALL_FUN_APP" />
<property name="dbGroupKey" value="TMALL_FUN_GROUP" />
</bean>
<bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="configLocation" value="classpath:dao/mybatis-config.xml"/>
<property name="mapperLocations" value="classpath:dao/mapper/*.xml"/>
</bean>
<bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate">
<constructor-arg index="0" ref="sqlSessionFactoryBean"/>
</bean>
<bean id="transactionManager"
class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource" />
</bean>
</beans>