1、不管condition是否满足，后面跟着的入参如果是表达式的都会去执行，所以要进行判空处理npe
1 lambdaQuery().setEntity(ObjectUtils.copy(param, EvaluationDO.class)) 2 .ge(Objects.nonNull(param.getRateGe()), EvaluationDO::getRate, Objects.isNull(param.getRateGe())? null: Math.toIntExact(EvaluationRateUtil.mul100(param.getRateGe())))
2、处理模糊查询，匹配两个字段
lambdaQuery().setEntity(qryDO) .in(!Objects.isNull(param.getIds()), CommunityPostDO::getId, param.getIds()) .like(StringUtils.isNotBlank(param.getTitleLike()), CommunityPostDO::getTitle, param.getTitleLike()) .and(StringUtils.isNotBlank(param.getKeywords()), (queryWrapper -> queryWrapper.like(CommunityPostDO::getTitle, param.getKeywords()) .or() .like(CommunityPostDO::getContent, param.getKeywords()))) .ge(Objects.nonNull(param.getPublishTimeStart()), CommunityPostDO::getGmtCreated, param.getPublishTimeStart()) .le(Objects.nonNull(param.getPublishTimeEnd()), CommunityPostDO::getGmtCreated, param.getPublishTimeEnd())
3、排序
1 .orderByDesc(Objects.equals(CommunitySortTypeEnum.HOT.getType(), param.getSortType()) ? 2 CommunityPostDO::getHot : 3 Objects.equals(CommunitySortTypeEnum.LATEST.getType(), param.getSortType()) ? 4 CommunityPostDO::getGmtCreated : 5 CommunityPostDO::getGmtModified)
4、大于小于，ge/le
1 lambdaQuery().setEntity(qryDO) 2 .ge(Objects.nonNull(param.getPublishTimeStart()), CommunityPostDO::getGmtCreated, param.getPublishTimeStart()) 3 .le(Objects.nonNull(param.getPublishTimeEnd()), CommunityPostDO::getGmtCreated, param.getPublishTimeEnd())
原文：https://www.cnblogs.com/jijiecong/p/15089260.html