GraduationDesign/errand/springboot/target/classes/mapper/UserMapper.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="com.example.mapper.UserMapper">

    <insert id="insert" parameterType="com.example.entity.User" useGeneratedKeys="true" keyProperty="id">
        insert into user
        <trim prefix="(" suffix=")" suffixOverrides=",">
            <if test="id != null">id,</if>
            <if test="username != null">username,</if>
            <if test="password != null">password,</if>
            <if test="name != null">name,</if>
            <if test="avatar != null">avatar,</if>
            <if test="role != null">role,</if>
            <if test="sex != null">sex,</if>
            <if test="phone != null">phone,</if>
            <if test="account != null">account,</if>
        </trim>
        <trim prefix="values (" suffix=")" suffixOverrides=",">
            <if test="id != null">#{id},</if>
            <if test="username != null">#{username},</if>
            <if test="password != null">#{password},</if>
            <if test="name != null">#{name},</if>
            <if test="avatar != null">#{avatar},</if>
            <if test="role != null">#{role},</if>
            <if test="sex != null">#{sex},</if>
            <if test="phone != null">#{phone},</if>
            <if test="account != null">#{account},</if>
        </trim>
    </insert>

    <update id="updateById">
        update user
        <set>
            <if test="username != null">
                username = #{username},
            </if>
            <if test="password != null">
                password = #{password},
            </if>
            <if test="name != null">
                name = #{name},
            </if>
            <if test="avatar != null">
                avatar = #{avatar},
            </if>
            <if test="role != null">
                role = #{role},
            </if>
            <if test="sex != null">
                sex = #{sex},
            </if>
            <if test="phone != null">
                phone = #{phone},
            </if>
            <if test="account != null">
                account = #{account},
            </if>
        </set>
        where id = #{ id }
    </update>

    <delete id="deleteById">
        delete from user where id = #{id}
    </delete>
    <select id="selectById" resultType="com.example.entity.User">
        select * from user where id = #{id}
    </select>
    <select id="selectAll" resultType="com.example.entity.User">
        select * from user
        <where>
            <if test="id != null"> and id= #{id}</if>
            <if test="username != null"> and username like concat('%', #{username}, '%')</if>
            <if test="name != null"> and name like concat('%', #{name}, '%')</if>
            <if test="sex != null"> and sex  = #{ sex }</if>
        </where>
    </select>
    <select id="selectByUsername" resultType="com.example.entity.User">
        select * from user where username = #{userename}
    </select>
</mapper>