Java实现分页查询的方法-优快云博客

本文介绍了在Java中实现分页查询的一种方式，通过在serviceImpl中设置分页参数并利用PageHelper进行分页，然后将查询结果转换为DTO对象，包含详细的数据填充过程。

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分页查询

serviceImpl

public PageInfo<ProjectDTO> getPage(Integer pageNum, Integer pageSize, ProjectParam projectParam) {

Project project = new Project();

project.setName(projectParam.getName());

project.setProjectType(projectParam.getProjectType());

project.setIsSubmit(true); project.setAreaIdList(userAreaService.getSonIdList(UserUtil.

getCurrentAreaId()));

Page page = PageHelper.startPage(pageNum, pageSize);

List<Project>projectList=projectMapper.selectList(project);

List<ProjectDTO> dtoList = Lists.newArrayList();

for (Project item : projectList) {

ProjectDTO dto = ProjectDTO.adapt(item);

BeanUtils.copyProperties(item,dto); dto.setAreaName(userAreaService.getById(item.getAreaId()).

getUserAreaName()); dto.setOwnerUnitName(ownerUnitService.getById(

item.getOwnerUnitId()).getName());

dto.setBuildingCount(projectPlanService.getCountByProjectId(item.getId()));

dtoList.add(dto);}

PageInfo pageInfo = new PageInfo(page);

pageInfo.setList(dtoList);

return pageInfo;}

serviceImpl

public PageModel<Product> page(ProductListRequest params) {
    IPage<ProductEntity> productEntitiesIPage = dao.getProductListByAdmin(
            params.getKeywords(),
            params.getCategoryId(),
            params.getProductId(),
            params.getLaunchStatus(),
            params.getStartCreateTime(),
            params.getEndCreateTime(),
            Optional.ofNullable(params.getSortedBy()).orElse("product_id"),
            Optional.ofNullable(params.getSortedType()).orElse("desc"),
            //分页参数
            new Page<>(params.getPageNum(), params.getPageSize()));
    List<Product> products = new ArrayList<>();
    productEntitiesIPage.getRecords().forEach(item -> products.add(factory.build(item)));
    PageModel<Product> productPage = new PageModel<>();
    productPage.setPageNum((productEntitiesIPage.getCurrent()));
    productPage.setPageSize(productEntitiesIPage.getSize());
    productPage.setTotal(productEntitiesIPage.getTotal());
    productPage.setRows(products);
    return productPage;
}