LambdaQueryWrapper&QueryWrapper增删改CURD使用教程案例

最新推荐文章于 2025-10-27 10:46:53 发布

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本文详细介绍了MyBatis中使用LambdaQueryWrapper进行数据查询、范围筛选、模糊匹配、空值比较、分组排序、拼接及嵌套SQL等操作的方法，包括eq、ne、gt等比较操作，between、in、like等范围和模糊匹配，以及group、order等分组排序技巧。此外，还展示了如何利用Lambda表达式简化查询条件。

1、【大小比较： ( =, <>, >, >=, <, <= )】

eq(R column, Object val); // 等价于 =，例: eq(“name”, “媳妇”) —> name = ‘媳妇’
ne(R column, Object val); // 等价于 <>，例: ne(“name”, “媳妇”) —> name <> ‘媳妇’
gt(R column, Object val); // 等价于 >，例: gt(“name”, “媳妇”) —> name > ‘媳妇’
ge(R column, Object val); // 等价于 >=，例: ge(“name”, “媳妇”) —> name >= ‘媳妇’
lt(R column, Object val); // 等价于 <，例: lt(“name”, “媳妇”) —> name < ‘媳妇’
le(R column, Object val); // 等价于 <=，例: le(“name”, “媳妇”) —> name <= ‘媳妇’

代码示例

public List<DimDict> listByDictCode(DictCodeEnum dictCodeEnum) {

        LambdaQueryWrapper<DimDict> wrapper = Wrappers.lambdaQuery();

        wrapper.eq(DimDict::getDictCode, dictCodeEnum.getCode())

                .eq(DimDict::getEnabled, DictEnableEnum.VALID.getType());

        return this.list(wrapper);

2、【范围：（between、not between、in、not in）】

between(R column, Object val1, Object val2); // 等价于 between a and b, 例： between(“age”, 18, 30) —> age between 18 and 30
notBetween(R column, Object val1, Object val2); // 等价于 not between a and b, 例： notBetween(“age”, 18, 30) —> age not between 18 and 30
in(R column, Object… values); // 等价于字段 IN (v0, v1, …),例: in(“age”,{1,2,3}) —> age in (1,2,3)
notIn(R column, Object… values); // 等价于字段 NOT IN (v0, v1, …), 例: notIn(“age”,{1,2,3}) —> age not in (1,2,3)
inSql(R column, Object… values); // 等价于字段 IN (sql 语句), 例: inSql(“id”, “select id from table where id < 3”) —> id in (select id from table where id < 3)
notInSql(R column, Object… values); // 等价于字段 NOT IN (sql 语句)

代码示例

public IPage<TbmNewsDupFilter> getInfoListByNewsId(String newsId, Byte position, Date startTime, Date endTime, Integer current, Integer size) {

        IPage<TbmNewsDupFilter> page = new Page<>(current, size);

        LambdaQueryWrapper<TbmNewsDupFilter> lqw = new LambdaQueryWrapper<>();

        lqw.eq(TbmNewsDupFilter::getNewsId, newsId).ne(TbmNewsDupFilter::getPosition, 0)

                .between(TbmNewsDupFilter::getCreateTime, startTime, endTime);

        if (null != position) {

            lqw.eq(TbmNewsDupFilter::getPosition, position);

        lqw.orderByDesc(TbmNewsDupFilter::getCreateTime);

        return tbmNewsDupFilterMapper.selectPage(page, lqw);

3、【模糊匹配：（like）】

like(R column, Object val); // 等价于 LIKE ‘%值%’，例: like(“name”, “媳妇”) —> name like ‘%媳妇%’
notLike(R column, Object val); // 等价于 NOT LIKE ‘%值%’，例: notLike(“name”, “媳妇”) —> name not like ‘%媳妇%’
likeLeft(R column, Object val); // 等价于 LIKE ‘%值’，例: likeLeft(“name”, “媳妇”) —> name like ‘%媳妇’
likeRight(R column, Object val); // 等价于 LIKE ‘值%’，例: likeRight(“name”, “媳妇”) —> name like ‘媳妇%’

代码示例

private Map<String, Double> queryWeight() {

        QueryWrapper<TagWeight> wrapper = new QueryWrapper<>();

        wrapper.lambda().likeRight(TagWeight::getTagType, "101109");

        List<TagWeight> list = tagWeightService.list(wrapper);

        if (CollectionUtils.isEmpty(list)) {

            return Maps.newHashMap();

        return list.stream().collect(Collectors.toMap(TagWeight::getTagType, TagWeight::getWeight));

4、【空值比较：（isNull、isNotNull）】

isNull(R column); // 等价于 IS NULL，例: isNull(“name”) —> name is null
isNotNull(R column); // 等价于 IS NOT NULL，例: isNotNull(“name”) —> name is not null

代码示例

private List<HwSecuritiesInfo> getHwSecuritiesInfoList(Long jsid, int limit) {

        LambdaQueryWrapper<HwSecuritiesInfo> lambda = new LambdaQueryWrapper<>();

        lambda.isNotNull(HwSecuritiesInfo::getCompanyCode)

                .ne(HwSecuritiesInfo::getSecuritiesSection, EXCLUDE_SEUCRITIES_SECTION)

                .gt(HwSecuritiesInfo::getJsid, jsid)

                .orderByAsc(HwSecuritiesInfo::getJsid);

        lambda.last("limit " + limit);

        return hwSecuritiesInfoService.list(lambda);

5、【分组、排序：（group、having、order）】

groupBy(R… columns); // 等价于 GROUP BY 字段, …，例: groupBy(“id”, “name”) —> group by id,name
orderByAsc(R… columns); // 等价于 ORDER BY 字段, … ASC，例: orderByAsc(“id”, “name”) —> order by id ASC,name ASC
orderByDesc(R… columns); // 等价于 ORDER BY 字段, … DESC，例: orderByDesc(“id”, “name”) —> order by id DESC,name DESC
having(String sqlHaving, Object… params); // 等价于 HAVING ( sql语句 )，例: having(“sum(age) > {0}”, 11) —> having sum(age) > 11

代码示例

    public IPage<Ds> selectDistinctDsByPage(DsQueryForm queryForm) {

        Integer currentPage = queryForm.getCurrentPage();

        Integer pageSize = queryForm.getPageSize();

        Page<Ds> page = new Page<>(currentPage, pageSize);

        LambdaQueryWrapper<Ds> lqw = new LambdaQueryWrapper<>();

        //数据源编码， 媒体栏目， 信息来源参数只传了一个

        String dsCode = queryForm.getDsCode();

        String dsSourceName = queryForm.getDsSourceName();

        String dsNewsColumns = queryForm.getDsNewsColumns();

        if (!StringUtil.isEmpty(dsCode)) {

            lqw.likeRight(Ds::getDsCode, SqlUtil.escapeLike(dsCode));

            lqw.groupBy(Ds::getDsCode).having("count (0) >1");

        } else if (!StringUtil.isEmpty(dsSourceName)) {

            lqw.like(Ds::getDsSourceName, SqlUtil.escapeLike(dsSourceName));

            lqw.groupBy(Ds::getDsSourceName);

        } else if (!StringUtils.isEmpty(dsNewsColumns)) {

            lqw.like(Ds::getDsNewsColumns, SqlUtil.escapeLike(dsNewsColumns));

            lqw.groupBy(Ds::getDsNewsColumns);

        lqw.orderByAsc(Ds::getDsCode);

        return dsMapper.selectPage(page, lqw);

6、【拼接、嵌套 sql：（or、and、nested、apply）】

or(); // 等价于 a or b，例：eq(“id”,1).or().eq(“name”,“媳妇”) —> id = 1 or name = ‘媳妇’
or(Consumer consumer); // 等价于 or(a or/and b)，or 嵌套。例: or(i -> i.eq(“name”, “李白”).ne(“status”, “活着”)) —> or (name = ‘李白’ and status <> ‘活着’)
and(Consumer consumer); // 等价于 and(a or/and b)，and 嵌套。例: and(i -> i.eq(“name”, “李白”).ne(“status”, “活着”)) —> and (name = ‘李白’ and status <> ‘活着’)
nested(Consumer consumer); // 等价于 (a or/and b)，普通嵌套。例: nested(i -> i.eq(“name”, “李白”).ne(“status”, “活着”)) —> (name = ‘李白’ and status <> ‘活着’)
apply(String applySql, Object… params); // 拼接sql（若不使用 params 参数，可能存在 sql 注入），例: apply(“date_format(dateColumn,‘%Y-%m-%d’) = {0}”, “2008-08-08”) —> date_format(dateColumn,‘%Y-%m-%d’) = ‘2008-08-08’")
last(String lastSql); // 无视优化规则直接拼接到 sql 的最后，可能存若在 sql 注入。
exists(String existsSql); // 拼接 exists 语句。例: exists(“select id from table where age = 1”) —> exists (select id from table where age = 1)

代码示例

public Long calculateFileRealMd5(Long minId, Integer limit) {

        LambdaQueryWrapper<AnncFile> wrapper = new LambdaQueryWrapper<>();

        wrapper.eq(AnncFile::getUploadStatus, UploadStatusEnum.SUCCESS.getCode())

                .isNull(AnncFile::getRealFileMd5)

                .gt(AnncFile::getId, minId)

                .orderByAsc(AnncFile::getId)

                .last("limit " + limit);

        List<AnncFile> list = anncFileService.list(wrapper);

7、【QueryWrapper 条件：】

select(String… sqlSelect); // 用于定义需要返回的字段。例： select(“id”, “name”, “age”) —> select id, name, age
select(Predicate predicate); // Lambda 表达式，过滤需要的字段。
lambda(); // 返回一个 LambdaQueryWrapper

代码案例

private List<HwSecuritiesInfo> query(QueryParam param) {

        QueryWrapper<HwSecuritiesInfo> wrapper = new QueryWrapper<>();

        wrapper.lambda().gt(HwSecuritiesInfo::getId, param.getJsid())

                .orderByAsc(HwSecuritiesInfo::getId);

        wrapper.lambda().select(HwSecuritiesInfo::getId, HwSecuritiesInfo::getBusinessId, HwSecuritiesInfo::getCompanyCode);

        wrapper.last("limit " + param.getCount());

        return hwSecuritiesInfoService.list(wrapper);

8、【UpdateWrapper 条件：】

set(String column, Object val); // 用于设置 set 字段值。例: set(“name”, null) —> set name = null
etSql(String sql); // 用于设置 set 字段值。例: setSql(“name = ‘老公’”) —> set name = ‘老公’
lambda(); // 返回一个 LambdaUpdateWrapper

代码示例

public List<GelonghuiNews> selectGelonghuiNews(Long lastId) {

        QueryWrapper<GelonghuiNews> wrapper = new QueryWrapper<>();

        if (null == lastId) {

        wrapper.lambda().gt(GelonghuiNews::getJsid, lastId).eq(GelonghuiNews::getImageStatus,OssImageStatus.YES.getStatus());

        return super.baseMapper.selectList(wrapper);

9、 LambdaQueryWrapper使用其实更为方便；

代码示例：

public List<TbmNewsPopularFeelings> selectNewsPopularFeelings(Date startTime, Date endTime, Integer limitSize) {

        LambdaQueryWrapper<TbmNewsPopularFeelings> lambdaQueryWrapper = new LambdaQueryWrapper<>();

        lambdaQueryWrapper.ge(startTime != null, TbmNewsPopularFeelings::getCreateTime, startTime);

        lambdaQueryWrapper.le(endTime != null, TbmNewsPopularFeelings::getCreateTime, endTime);

        lambdaQueryWrapper.orderByAsc(TbmNewsPopularFeelings::getCreateTime);

        lambdaQueryWrapper.last("limit " + limitSize);

        return historyNewsEventMapper.selectList(lambdaQueryWrapper);