代码简便写法

一、拼接字符串并用逗号分隔

public class StuTest {
    public static void main(String[] args) {
        Stu stu1 = new Stu(1, "zhangsan");
        Stu stu2 = new Stu(2, "lisi");
        List<Stu> list = new ArrayList<>();
        list.add(stu1);
        list.add(stu2);
        String result = list.stream().map(Stu::getName).collect(Collectors.joining(","));
        System.out.println(result.toString());
    }
}

二、在sql中进行判断逻辑

<sql id="sql-count-where">
        <choose>
            <when test="param.basicIdList == null">
                and 1 = 1
            </when>
            <when test="param.basicIdList != null and param.basicIdList.size > 0">
                and aci.basic_id in
                <foreach collection="param.basicIdList" index="index" item="item" open="(" close=")" separator=",">
                    #{item}
                </foreach>
            </when>
            <otherwise>
                and 1 = -1
            </otherwise>
        </choose>
    </sql>

三、使用正则切割字符串

public static final String ORDER_NO_SPLIT_REGEX = ",|，|;|；| |\t|\n|\r";

private List<String> getorderOrWaybillNoList(String orderNoOrWaybillNo) {
    if (StringUtils.isBlank(orderNoOrWaybillNo)) {
        return Lists.newArrayList();
    }
    String[] split = orderNoOrWaybillNo.split(ORDER_NO_SPLIT_REGEX);
    List<String> orderNoOrWaybillNos = com.google.common.collect.Lists.newArrayList(split);
    List<String> orderNoOrWaybillNoList = orderNoOrWaybillNos.stream().filter(o -> StringUtils.isNotBlank(o)).distinct().collect(Collectors.toList());
    if (CollectionUtils.isEmpty(orderNoOrWaybillNoList)) {
        logger.info("切出的单号集合为空", JSON.toJSONString(split));
    }
    return orderNoOrWaybillNoList;
}

四、条件语句中的循环模糊查询

<if test="param.businessType == 2 and param.waybillNoList != null and param.waybillNoList.size>0">
    and
    (
      <foreach collection="param.waybillNoList" separator="or" item="waybillNo" index="index">
          aci.business_no like concat('%', #{waybillNo},'%')
      </foreach>
    )
</if>