JAVA手动分页

最新推荐文章于 2024-05-10 21:17:44 发布

原创最新推荐文章于 2024-05-10 21:17:44 发布 · 143 阅读

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#java

该代码段展示了如何在Java中进行动态分页处理，包括获取PageInfo对象以及创建PageBaseVo对象来封装分页数据。方法中涉及到对列表的切片操作，计算总页数，并根据当前页和每页大小进行调整。

public static <T> PageInfo<T> getPageInfo(int currentPage, int pageSize, List<T> list) {
    int total = list.size();
    if (total > pageSize) {
        int toIndex = pageSize * currentPage;
        if (toIndex > total) {
            toIndex = total;
        }
        list = list.subList(pageSize * (currentPage - 1), toIndex);
    }
    Page<T> page = new Page<>(currentPage, pageSize);
    page.addAll(list);
    page.setPages((total + pageSize - 1) / pageSize);
    page.setTotal(total);

    PageInfo<T> pageInfo = new PageInfo<>(page);
    return pageInfo;
}

/**
 * 手动分页
 *
 * @param list     分页的结果集
 * @param pageNum  当前页页码
 * @param pageSize 每页的数量
 */
public PageBaseVo(List<T> list, Integer pageNum, Integer pageSize) {
    int total = list.size();
    pageNum = pageSize == null || pageNum == 0 ? 1 : pageNum;
    pageSize = pageSize == null || pageSize == 0 ? total : pageSize;
    int fromIndex = (pageNum - 1) * pageSize;
    int toIndex = fromIndex + pageSize;
    this.pageNum = pageNum;
    this.pageSize = pageSize;
    this.total = (long) total;
    this.pages = (total - 1) / (pageSize + 1);
    if (fromIndex >= total) {
        this.size = 0;
        this.list = new ArrayList<>();
        return;
    }
    if (toIndex > total) {
        toIndex = total;
    }
    this.size = toIndex - fromIndex;
    this.list = list.subList(fromIndex, toIndex);
}

PageInfo<Res> pageInfo = PageBaseVo.getPageInfo(req.getPageNum(),req.getPageSize(),list);
return new PageBaseVo<>(pageInfo, pageInfo.getList());