mybatis 配置说明和类结构图

配置数据源

数据源配置

<configuration> 
<environments default="development"> 
<environment id="development"> 
<transactionManager type="JDBC"/> 
<dataSource type="POOLED"> 
<property name="driver" value="${driver}"/> 
<property name="url" value="${url}"/> 
<property name="username" value="${username}"/> 
<property name="password" value="${password}"/> 
</dataSource> 
</environment> 
</environments> 
</configuration>

相关配置配置文件

<mappers> 
<mapper resource="org/mybatis/builder/AuthorMapper.xml"/> 
<mapper resource="org/mybatis/builder/BlogMapper.xml"/> 
<mapper resource="org/mybatis/builder/PostMapper.xml"/> 
</mappers> 
// Using url fully qualified paths 
<mappers> 
	<mapper url="file:///var/sqlmaps/AuthorMapper.xml"/> 
	<mapper url="file:///var/sqlmaps/BlogMapper.xml"/> 
	<mapper url="file:///var/sqlmaps/PostMapper.xml"/> 
</mappers>

SQL映射配置

SQL 映射文件结构：
  cache -  配置给定命名空间的缓存。 
  cache-ref –  从其他命名空间引用缓存配置。 
  resultMap  –  最复杂，也是最有力量的元素，用来描述如何从数据库结果集中来加载你的对象。 
  parameterMap  –  已经被废弃了！老式风格的参数映射。内联参数是首选，这个元素可能在将来被移除。这里不会记录。 
  sql –  可以重用的 SQL 块，也可以被其他语句引用。 
  insert –  映射插入语句 
  update –  映射更新语句 
  delete –  映射删除语句 
  select –  映射查询语句

Sql Select配置

Select
<mapper namespace="org.mybatis.example.BlogMapper"> 
	<select id="selectBlog" parameterType="int" resultType="Blog"> 
		select * from Blog where id = #{id} 
	</select> 
</mapper>
第一种使用完全限定名调用映射语句
Blog blog = (Blog) session.selectOne( 
"org.mybatis.example.BlogMapper.selectBlog", 101);

第二种采用映射接口调用映射语句
BlogMapper mapper = session.getMapper(BlogMapper.class); 
Blog blog = mapper.selectBlog(101);

Sql insert配置

如果 Author 表已经对 id 使用了自动生成的列类型
<insert id="insertAuthor" parameterType="domain.blog.Author" 
	useGeneratedKeys=”true” keyProperty=”id”> 
		insert into Author (username,password,email,bio) 
		values (#{username},#{password},#{email},#{bio}) 
</insert> 
如果Author表主键生成策略采用OID、Sequence
<insert id="insertAuthor" parameterType="domain.blog.Author"> 
	<selectKey resultType="Long" keyProperty="id" order="BEFORE"> 	
		select nextval FOR AUTHOR_SEQ from SYSIBM.SYSDUMMY1
 	</selectKey>
insert into Author (id, username, password, email,bio, favourite_section) 
values 
(#{id}, #{username}, #{password}, #{email}, #{bio}, 
#{favouriteSection,jdbcType=VARCHAR} ) 
</insert>

Sql update和Delete配置

Update
<update id="updateAuthor" parameterType="domain.b
	update Author set 
	username = #{username}, 
	password = #{password}, 
	email = #{email}, 
	bio = #{bio} 
	where id = #{id} 
</update> 
Delete
<delete id="deleteAuthor” parameterType="int"> 
	delete from Author where id = #{id} 
</delete>

动态sql

示例一

<select id=“findActiveBlogLike” 
		parameterType=”Blog” resultType=“Blog”> 
		SELECT * FROM BLOG
		WHERE state = “ACTIVE” 
			<if test=”title != null”> 
				AND title like #{title} 
			</if> 
			<if test=”author != null and author.name != null”> 
				AND title like #{author.name} 
			</if> 
</select>

实例二

<select id=”findActiveBlogLike” 
		parameterType=”Blog” resultType=”Blog”> 
	SELECT * FROM BLOG 
	<where> 
		<if test=”state != null”> 
			state = #{state} 
		</if> 
		<if test=”title != null”> 
			AND title like #{title} 
		</if> 
	</where> 
</select>

缓存配置

<cache/>

缓存示例

<cache 
	eviction="FIFO" 
	flushInterval="60000" 
	size="512" 
	readOnly="true"/>

这个配置创建了一个 FIFO 缓存，并每隔 60 秒刷新，存取512 个结果对象或列表的引用，而且返回的对象为只读，因此在不同线程中的调用者之间修改它们会导致冲突。

自定义cache配置

自定义Cache
<cache type=”com.domain.something.MyCustomCache”> 
	<property name=”cacheFile” value=”/tmp/my-custom-cache.tmp”/> 
</cache>
Ehcache
<mapper namespace="org.acme.FooMapper">
	<cache type="org.mybatis.ehcache.EhcacheCache"/>
	...
</mapper>
OSCache
<mapper namespace="org.acme.FooMapper">
<cache type="org.mybatis.oscache.OSCache"/>
	...
</mapper>

整合spring

<bean id="sqlSessionFactory"
	class="org.springframework.orm.ibatis3.SqlSessionFactoryBean">
	<property name="configLocation"
		value="classpath:SqlMapConfig.xml" />
	<property name="dataSource" ref="dataSource" />
</bean>

假设类 UserMapperImpl是 SqlSessionDaoSupport的子类，它可以在 Spring 中进行如下的配置：

<bean id="userMapper" class="org.mybatis.spring.sample.mapper.UserMapperImpl"> 
	<property name="sqlSessionFactory" ref="sqlSessionFactory" /> 
</bean>

mybatis类图