1.Mybatis映射文件的<select>标签主要帮助我们完成SQL语句查询功能，<select>标签它包含了很多属性，下面简单对<select>标签的属性做一个归纳
- id：唯一指定标签的名字
- resultType：查询结构返回的数据类型，自动进行封装操作
- parameterType：给SQL语句传递参数的数据类型
- resultMap：查询结果返回的数据类型，会根据映射文件中<resultMap>来完成数据封装
- parameterMap：给SQL语句传递参数的数据类型，需要和<parameterMap…/>标签连用
2.下面代码主要说明resultMap和parameterType的用法
<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.gxa.mapper.TeamMapper"> <resultMap type="com.gxa.pojo.Team" id="Team"> <id column="t_id" property="tid"/> <result column="t_name" property="tname"/> </resultMap> <select id="getTeam" resultMap="Team"> select * from team </select> <select id="getTeamById" resultMap="Team" parameterType="java.lang.Integer"> select * from team where t_id = #{tid} </select> <select id="getTeamById2" resultMap="Team" parameterType="com.gxa.pojo.Team"> select * from team where t_id = #{tid} and t_name = #{tname} </select> </mapper>3.下面代码主要说明resultType的用法
<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.gxa.mapper.MyUserMapper"> <select id="getMyUser" resultType="com.gxa.pojo.MyUser" > select * from myuser </select> </mapper>