Mybatis使用问题汇总

JDK1.8分组问题产生的SQL需求

需求一

传入的值数据结构为：List(Map<String, String>)

Dao层的代码：

List<RecordPo> selectConditionRecord(List<Map<String, String>> list);

xml层代码：

<select id="selectConditionRecord" resultMap="BaseResultMap" parameterType="java.util.List">
    <foreach collection="list" item="item" index="index" separator=";">
        select
        *
        from
        RECORD
        <where>
            <if test="item.code != null and item.code != ''">
                code = #{item.code,jdbcType=VARCHAR}
            </if>
            <if test="item.account != null and item.account != ''">
                and account = #{item.account,jdbcType=VARCHAR}
            </if>
            <if test="item.createdate != null">
                and to_char(CREATEDATE, 'yyyy-MM-dd') = #{item.createdate,jdbcType=TIMESTAMP}
            </if>
        </where>
    </foreach>
</select>

需求二

mybatis批量更新问题
传入的值数据结构为：List(Map<String, String>)

Dao层的代码：

void batchUpdate(List<RecordPo> list);

xml层代码：

<update id="batchUpdate" parameterType="java.util.List">
    <foreach collection="list" index="index" item="item" separator=";">
        update RECORD
        <set>
            <if test="item.id != null">
                id = #{item.id,jdbcType=VARCHAR},
            </if>
            <if test="item.code != null">
                code = #{item.code,jdbcType=VARCHAR},
            </if>
            <if test="item.createuser != null">
                createuser = #{item.createuser,jdbcType=VARCHAR},
            </if>
            <if test="item.createdate != null">
                createdate = #{item.createdate,jdbcType=TIMESTAMP},
            </if>
        </set>
        <where>
            id = #{item.id,jdbcType=VARCHAR}
        </where>
    </foreach>
</update>

• 出现的问题：

Cause: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax;

check the manual that corresponds to your MySQL server version for the right syntax to use near 'UPDATE hd_t_user\n             SET username ='111' \n            where\n           ' at line 6\r\n### The error may exist in file；

• 解决方案：

allowMultiQueries=true