dao中定义方法：

List<KeyValueEntity> groupByDay(Date startDate, Date endDate);

在早期，参数没做注解时默认是按顺序获取，以0、1等为索引，所以Mapper是这样写的：

    <select id="groupByDay" resultType="io.renren.modules.business.entity.template.KeyValueEntity">
        select DATE_FORMAT(create_time, '%Y/%m/%d') as keyText, count(*) as value
        from question_answer
        where create_time BETWEEN #{0, jdbcType=DATE} AND #{1, jdbcType=DATE}
        group by keyText
        order by keyText
    </select>

后来由0、1改为用arg0、arg1代替：

    <select id="groupByDay" resultType="io.renren.modules.business.entity.template.KeyValueEntity">
        select DATE_FORMAT(create_time, '%Y/%m/%d') as keyText, count(*) as value
        from question_answer
        where create_time BETWEEN #{arg0, jdbcType=DATE} AND #{arg1, jdbcType=DATE}
        group by keyText
        order by keyText
    </select>

而新版的又改成以参数名使用：

    <select id="groupByDay" resultType="io.renren.modules.business.entity.template.KeyValueEntity">
        select DATE_FORMAT(create_time, '%Y/%m/%d') as keyText, count(*) as value
        from question_answer
        where create_time BETWEEN #{startDate, jdbcType=DATE} AND #{endDate, jdbcType=DATE}
        group by keyText
        order by keyText
    </select>

对于当前库的强制更新，可以使用命令：

mvn clean install -U

对于下面打包命令，也是会使用新库：

mvn clean package