Spring Boot Jpa封装快速构建Specification、OrderBy、Pageable的查询条件

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1、简介

在我们使用JPA时，构建 Specification 查询条件时重复代码过多，而且需要大量的无效代码。

2、工具类提供的方法

2.1、自动构建规范

  /**
   * 自动构建规范
   *
   * @param builder JapCriteriaBuilder
   * @param entity  实体
   * @param <V>     实体类型
   * @return Specification
   */
  public <V> JpaCriteriaBuilder<T> autoBuilder(JpaCriteriaBuilder<T> builder, @NotNull V entity, @NotNull Class<T> clazz) {
    if (Objects.isNull(entity)) {
      throw new GlobalRuntimeException("实体不能为空");
    }
    List<String> ignoreFields = List.of("serialVersionUID");
    List<Field> fields = getDeclaredFields(clazz);
    for (Field field : fields) {
      if (field == null || Modifier.isStatic(field.getModifiers())) {
        continue;
      }
      try {
        field.setAccessible(Boolean.TRUE);
        Object value = ReflectionUtils.getFieldValue(entity, field.getName());
        if (StringUtils.isNullAndSpaceOrEmpty(value) || ignoreFields.contains(field.getName())) {
          continue;
        }
        builder = builder.equal(field.getName(), value);
      } catch (Exception e) {
        LOG.error(e, "自动构建规范异常");
      }
    }

    // 分页数据
    String pageSize = "pageSize", pageIndex = "pageIndex";
    Object value = ReflectionUtils.getFieldValue(entity, pageIndex);
    if (StringUtils.isNotNullAndEmpty(value)) {
      builder = builder.page(ConvertUtils.convertInt(value));
    }
    // 页码大小
    value = ReflectionUtils.getFieldValue(entity, pageSize);
    if (StringUtils.isNotNullAndEmpty(value)) {
      builder = builder.size(ConvertUtils.convertInt(value));
    }

    // 返回结果
    return builder;
  }

2.2 分组或过虑字段构建规范

2.3 添加等值查询条件

  /**
   * 添加等值查询条件
   *
   * @param field 字段
   * @param value 值
   * @param <V>   泛型
   * @return JapCriteriaBuilder
   */
  public <V> JpaCriteriaBuilder<T> equal(@NotNull String field, @NotNull V value) {
    if (isValidValue(value)) {
      specification = specification.and((root, query, criteriaBuilder) ->
          criteriaBuilder.equal(root.get(field), value)
      );
    }
    return this;
  }

2.4 添加模糊查询条件

  /**
   * 添加模糊查询条件
   *
   * @param field 字段
   * @param value 值
   * @param <V>   泛型
   * @return JapCriteriaBuilder
   */
  public <V> JpaCriteriaBuilder<T> like(@NotNull String field, @NotNull V value) {
    if (isValidValue(value)) {
      specification = specification.and((root, query, criteriaBuilder) -> {
        String pattern = StringUtils.PERCENT + value + StringUtils.PERCENT;
        return criteriaBuilder.like(root.get(field), pattern);
      });
    }
    return this;
  }

2.5  添加 in 查询条件

  /**
   * 添加in查询条件
   *
   * @param field  字段
   * @param values 值
   * @param <V>    泛型
   * @return JapCriteriaBuilder
   */
  public <V> JpaCriteriaBuilder<T> in(@NotNull String field, @NotNull List<V> values) {
    if (CollectUtils.isNotEmpty(values)) {
      specification = specification.and((root, query, criteriaBuilder) ->
          root.get(field).in(values)
      );
    }
    return this;
  }

2.6 添加大于查询条件

  /**
   * 添加大于查询条件
   *
   * @param field 字段
   * @param value 值
   * @param <V>   泛型
   * @return JapCriteriaBuilder
   */
  public <V extends Comparable<? super V>> JpaCriteriaBuilder<T> greaterThan(@NotNull String field, @NotNull V value) {
    if (isValidValue(value)) {
      specification = specification.and((root, query, criteriaBuilder) ->
          criteriaBuilder.greaterThan(root.get(field), value)
      );
    }
    return this;
  }

2.7 添加大于等于查询条件

  /**
   * 添加大于等于查询条件
   *
   * @param field 字段
   * @param value 值
   * @param <V>   泛型
   * @return JapCriteriaBuilder
   */
  public <V extends Comparable<? super V>> JpaCriteriaBuilder<T> greaterThanOrEqualTo(@NotNull String field, @NotNull V value) {
    if (isValidValue(value)) {
      specification = specification.and((root, query, criteriaBuilder) ->
          criteriaBuilder.greaterThanOrEqualTo(root.get(field), value)
      );
    }
    return this;
  }

2.8 添加小于查询条件

  /**
   * 添加小于查询条件
   *
   * @param field 字段
   * @param value 值
   * @param <V>   泛型
   * @return JapCriteriaBuilder
   */
  public <V extends Comparable<? super V>> JpaCriteriaBuilder<T> lessThan(@NotNull String field, @NotNull V value) {
    if (isValidValue(value)) {
      specification = specification.and((root, query, criteriaBuilder) ->
          criteriaBuilder.lessThan(root.get(field), value)
      );
    }
    return this;
  }

2.9 添加区间查询条件

  /**
   * 添加区间查询条件
   *
   * @param field 字段
   * @param from  区间起始值
   * @param to    区间结束值
   * @param <V>   泛型
   * @return JapCriteriaBuilder
   */
  public <V extends Comparable<? super V>> JpaCriteriaBuilder<T> between(@NotNull String field, @NotNull V from, V to) {
    if (from != null && to != null) {
      specification = specification.and((root, query, criteriaBuilder) ->
          criteriaBuilder.between(root.get(field), from, to)
      );
    }
    return this;
  }

2.10 添加空查询条件

  /**
   * 添加空查询条件
   *
   * @param field 字段
   * @return JapCriteriaBuilder
   */
  public JpaCriteriaBuilder<T> isNull(String field) {
    specification = specification.and((root, query, criteriaBuilder) ->
        criteriaBuilder.isNull(root.get(field))
    );
    return this;
  }

2.11 添加非空查询条件

  /**
   * 添加非空查询条件
   *
   * @param field 字段
   * @return JapCriteriaBuilder
   */
  public JpaCriteriaBuilder<T> isNotNull(String field) {
    specification = specification.and((root, query, criteriaBuilder) ->
        criteriaBuilder.isNotNull(root.get(field))
    );
    return this;
  }

2.12 添加关联查询条件

  /**
   * 添加关联查询条件
   *
   * @param joinField 关联字段
   * @param field     字段
   * @param value     值
   * @param joinType  关联类型
   * @param <X>       关联实体类型
   * @return JapCriteriaBuilder
   */
  public <X> JpaCriteriaBuilder<T> joinEqual(String joinField, @NotNull String field, @NotNull Object value, JoinType joinType) {
    if (isValidValue(value)) {
      specification = specification.and((root, query, criteriaBuilder) -> {
        Join<T, X> join = root.join(joinField, joinType);
        return criteriaBuilder.equal(join.get(field), value);
      });
    }
    return this;
  }

2.13 添加自定义查询条件

  /**
   * 添加自定义查询条件
   *
   * @param condition 自定义查询条件
   * @return JapCriteriaBuilder
   */
  public JpaCriteriaBuilder<T> add(Function<Root<T>, Predicate> condition) {
    specification = specification.and((root, query, criteriaBuilder) -> {
      Predicate predicate = condition.apply(root);
      return criteriaBuilder.and(predicate);
    });
    return this;
  }

2.14 或查询

  /**
   * 或查询
   *
   * @param otherBuilder 其他查询条件
   * @return JapCriteriaBuilder
   */
  public JpaCriteriaBuilder<T> or(JpaCriteriaBuilder<T>... otherBuilder) {
    // 创建一个新的 Specification 来存储合并后的查询条件
    Specification<T> combinedSpecification = Specification.where(specification);

    // 遍历所有传入的 JapCriteriaBuilder
    for (JpaCriteriaBuilder<T> builder : otherBuilder) {
      combinedSpecification = combinedSpecification.or(builder.build());
    }

    // 更新当前的 specification 为合并后的结果
    specification = combinedSpecification;
    return this;
  }

2.15 页码

  /**
   * 页码
   *
   * @param page 页码
   * @return JapCriteriaBuilder
   */
  public JpaCriteriaBuilder<T> page(int page) {
    this.pageNumber = page;
    return this;
  }

2.16 每页大小

  /**
   * 每页大小
   *
   * @param size 每页大小
   * @return JapCriteriaBuilder
   */
  public JpaCriteriaBuilder<T> size(int size) {
    this.pageSize = size;
    return this;
  }

2.17 排序

  /**
   * 排序
   *
   * @param field     字段
   * @param direction 排序方向
   * @return JapCriteriaBuilder
   */
  public JpaCriteriaBuilder<T> orderBy(@NotNull String field, @NotNull Sort.Direction direction) {
    if (direction != null) {
      rawSortList.add(Sort.Order.by(field).with(direction));
    }
    return this;
  }

2.18 构建分页查询条件

  /**
   * 构建分页查询条件
   *
   * @return Pageable
   */
  public Pageable toPageable() {
    if (CollectUtils.isEmpty(rawSortList)) {
      throw new GlobalRuntimeException("分页查询必须指定排序条件");
    }
    return PageRequest.of(
        Objects.requireNonNullElse(pageNumber, IntegerConsts.ZERO),
        Objects.requireNonNullElse(pageSize, IntegerConsts.FIFTEEN),
        Sort.by(rawSortList)
    );
  }

2.19 构建查询条件

  /**
   * 构建查询条件
   *
   * @return Specification
   */
  public Specification<T> build() {
    return (root, query, cb) -> {
      // 应用排序条件
      if (!rawSortList.isEmpty()) {
        List<Order> orders = rawSortList.stream()
            .map(sortOrder -> {
              Path<Object> path = root.get(sortOrder.getProperty());
              return sortOrder.getDirection().isAscending() ? cb.asc(path) : cb.desc(path);
            })
            .collect(Collectors.toList());
        query.orderBy(orders);
      }
      // 生成查询条件
      return specification.toPredicate(root, query, cb);
    };
  }

3 使用示例

3.1 使用自动构建规范

    // 查询条件
    JpaCriteriaBuilder<WikiLicenseEntity> builder = JpaCriteriaBuilder.Builder();
    builder = builder.autoBuilder(builder, license);

    // 排序
    builder = builder.orderBy(WikiLicenseDto.ADD_TIME, Sort.Direction.DESC);

    // 分页
    builder = builder .page(license.getPageIndex() - IntegerConsts.ONE)
        .size(license.getPageSize());

    // 查询分页数据
    Page<WikiLicenseEntity> page = wikiLicenseRepository.findAll(builder.build(), builder.toPageable());

3.2 自定义添加查询条件

    // 查询条件
    JpaCriteriaBuilder<WikiLicenseEntity> builder = JpaCriteriaBuilder.Builder();
    builder.equal(WikiLicenseDto.DELETED, IntegerConsts.ZERO);
    builder.equal(WikiLicenseDto.STATUS, IntegerConsts.ONE);

    JpaCriteriaBuilder<WikiLicenseEntity> builderKey = JpaCriteriaBuilder.Builder();
    builderKey = builderKey.equal(WikiLicenseDto.KEY, license.getKey());

    JpaCriteriaBuilder<WikiLicenseEntity> builderName = JpaCriteriaBuilder.Builder();
    builderName = builderName.equal(WikiLicenseDto.NAME, license.getName());
    // 添加或查询
    builder = builder.or(builderKey, builderName);

    // 查询数据
    List<WikiLicenseEntity> licenseList = wikiLicenseRepository.findAll(builder.build());

4 总结

更多使用或者有更好的方法欢迎连续博主，完整的代码可查看博主开源的框架：维基框架

Gitee：https://gitee.com/cdkjframework/wiki-framework

Github：https://github.com/cdkjframework/wiki-framework

若觉得博主的项目还不错，希望你能给博主 star及fork。如果有其他需要了解的内容请留言，看到后会及时回复。

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