从iBATIS 2.x到MyBatis的变化

从iBATIS 2.x到MyBatis的变化

From iBATIS 2.x to MyBatis

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This page provides some information that is useful when migrating a project from iBatis 2 to MyBatis 3. It is probably not 100% complete.

Conversion Tool

There is a tool available in the downloads section that will help you to convert your iBATIS 2.x sqlmap files into MyBatis 3.x xml mapper files.

Get it from http://mybatis.googlecode.com/files/ibatis2mybatis.zip

The tool is designed around an xslt transformation and some text replacements packaged in an ant task and tries to deliver a good starting point before the more complex work begins.

New DTDs

New sqlMapConfig.xml DTD:

<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">

New sqlMap (*.map.xml) DTD:

<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 

Configuration

• Root configuration tag <sqlMapConfig> is now <configuration>

Settings

Within the root configuration tag:

<settings x="y" foo="bar"/>

is now:

<settings>    <setting name="x" value="y"/>    <setting name="foo" value="bar"/></settings>

and

<settings useStatementNamespaces="true"/>

can be removed, since the use of namespaces has become mandatory.

<typeAlias>

<typeAlias> must be moved out of the <sqlMap> element to <configuration><typeAliases></typeAliases></configuration>

<configuration>    <settings>    ...    </settings>    <typeAliases>        <typeAlias ... />    </typeAliases></configuration>

<transactionManager> and<dataSource>

<transactionManager type="JDBC" commitRequired="false">    <dataSource type="your.package.CustomDataSourceFactory" /></transactionManager>

is now:

<environments default="env">    <environment id="env">        <transactionManager type="JDBC">            <property name="commitRequired" value="false"/>        </transactionManager>        <dataSource type="your.package.CustomDataSourceFactory" />    </environment></environments>

<sqlMap>

<sqlMap resource=... /><sqlMap resource=... /><sqlMap resource=... />

is now:

<mappers>    <mapper resource=... /></mappers>

Mapping

• The root element <sqlMap> is now <mapper>
• The attribute parameterClass should be changed to parameterType
• The attribute resultClass should be changed to resultType
• The attribute class should be changed to type
• the columnIndex attribute does not exist anymore for the <result> tag
• The groupBy attribute has been eliminated. Here is an example of groupBy from a 2.x sqlMap:

<resultMap id="productRM" class="product" groupBy="id">    <result property="id" column="product_id"/>    <result property="name" column="product_name"/>    <result property="category" column="product_category"/>    <result property="subProducts" resultMap="Products.subProductsRM"/></resultMap>

New:

<resultMap id="productRM" type="product" >    <id property="id" column="product "/>    <result property="name " column="product_name "/>    <result property="category " column="product_category "/>    <collection property="subProducts" resultMap="Products.subProductsRM"/></resultMap>

Nested resultMaps

These should now be specified using the <association> tag.

<resultMap ...>    <result property="client" resultMap="Client.clientRM"/>    ...</resultMap>

is now:

<resultMap ...>    <association property="client" resultMap="Client.clientRM"/>    ...</resultMap>

<parameterMap>

Although this tag is deprecated, it can be used as in iBatis 2. However for versions up to 3.0.3 there is a bug when usingtype="map" and not specifying javaType for a parameter. This will result in

There is no getter for property named '...' in 'interface java.util.Map'    

This should be solved in MyBatis 3.0.4. For versions 3.0.3 and earlier the workaround is to explicitly specifyjavaType.

Inline parameters

#value#

is now:

#{value}

jdbcType changes

jdbcType="ORACLECURSOR"

is now:

jdbcType="CURSOR"

and

jdbcType="NUMBER"

is now:

jdbcType="NUMERIC"

Stored procedures

• the <procedure> tag doesn't exist anymore. Use <select>, <insert> or <update>.

<procedure id="getValues" parameterMap="getValuesPM">    { ? = call pkgExample.getValues(p_id => ?) }</procedure>

is now:

<select id="getValues" parameterMap="getValuesPM" statementType="CALLABLE">    { ? = call pkgExample.getValues(p_id => ?)}</select>

If you're calling an insert procedure that returns a value, you can use<select> instead of <insert>, but make sure to specify useCache="false" andflushCache="true". You'll also have to force a commit.

• for stored procedures that return a cursor, there is a bug (see  issue 30 ) when using nested result maps (i.e. the output parameter's resultMap contains an<association> tag with the resultMap attribute). As long as the issue is not fixed, you have to specify the resultMap of the output parameter on the statement itself as well, or the nested resultMap will not be populated.

Caching

<cacheModel id="myCache" type="LRU">    <flushInterval hours="24"/>    <property name="size" value="100" /></cacheModel>

is now:

<cache flushInterval="86400000" eviction="LRU"/>

Note: you can omit eviction="LRU" since it is the default.

• the <flushOnExecute> tag is replaced by the flushCache attribute for the statements and the cache will be used by all select statements by default.

Dynamic SQL

The most common dynamic SQL in my project is isNotNull. Here is an example replacement regex:

Pattern:

<isNotNull.*?property=\"(.*?)\"></isNotNull>

Replacement:

<if test="$1 != null"></if>

Also common is the use of isEqual, you can replace this by a similar <if> tag.

Java code

SqlMapClient

• This class doesn't exist anymore. Use SqlSessionFactory instead (see User Guide).

Custom type handler

• Replace interface TypeHandlerCallback with TypeHandler. It has slightly different but similar methods.

Custom data source factory

Old interface:

com.ibatis.sqlmap.engine.datasource.DataSourceFactory

New interface:

org.apache.ibatis.datasource.DataSourceFactory

Replace method

public void initialize(Map properties)

with

public void setProperties(Properties props)