mybatis是一个数据持久层(orm)框架
与传统的JDBC比较减少了61%的代码量
有2个文件1个接口
configuration.xml 全局配置文件
mapper.xml 核心配置文件 映射文件写sql语句的
sqlSession 接口
别名alias
在核心配置文件中
<typeAliases>
<typeAlias alias="stu" type="com.yunhe.bean.StudentBean"/>
</typeAliases>
如果数据库中列名与mybatis中不一致
<mapper namespace="com.yunhe.dao.StudentDao">
<select id="selectAll" resultType="stu">
select id as id,name as name,age as age,sex as sex from student
</select>
例子:
configuration.xml 全局配置文件
<?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>
<properties resource="java.properties"/>
<!-- java类型的别名 -->
<typeAliases>
<typeAlias alias="stu" type="com.yunhe.bean.StudentBean"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="stu.xml"/>
</mappers>
</configuration>
另还需要一个跟全局配置搭配的数据库信息
java.properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/student
jdbc.username=root
jdbc.password=1234
stu.xml(mapper映射文件)
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.yunhe.dao.StudentDao">
<select id="selectAll" resultType="stu">
select id as id,name as name,age as age,sex as sex from student
</select>
</mapper>