xxxMapper.xml文件的头部配置

<?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.offcn.Mapper.MUserMapper">
    <select id="getUserList" resultType="com.offcn.POJO.MUser">
   　　 select * from user
  　</select>
</mapper>