Chat/src/main/resources/mapper/LoginMapper.xml

<?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="dao.Login">
    <select id="getUser" resultType="com.example.chat.entity.User">
        select *
        from user
        where account = #{account};
    </select>
    <select id="emailCheck" resultType="com.example.chat.entity.User">
        select *
        from user
        where email = #{email};
    </select>

    <insert id="addUser">
        insert into user(account, password, username, email, pic)
        values (#{account}, #{password}, #{username}, #{email}, #{pic});
    </insert>
    <delete id="delUser">
        delete
        from user
        where account = #{account};
    </delete>
    <update id="updateUser">
        update user
        set password=#{password} and username = #{username} and email = #{email}
        where account = #{account};
    </update>
    <update id="updateHead" parameterType="com.example.chat.entity.User">
        update user
        set pic=#{pic}
        where account = #{account}
    </update>
</mapper>