分页计算总页数

public class Pagination {

    private int total;       // 总记录数
    private int size;        // 每页记录数
    private int currentPage; // 当前页码
    private int totalPages;  // 总页数

    public Pagination(int total, int size) {
        this.total = total;
        this.size = size;
        this.currentPage = 1; // 默认当前页码为1
        calculateTotalPages();
    }

    // 计算总页数
    private void calculateTotalPages() {
        this.totalPages = (int) Math.ceil((double) total / size);
    }

    // 获取当前页码
    public int getCurrentPage() {
        return currentPage;
    }

    // 设置当前页码
    public void setCurrentPage(int currentPage) {
        if (currentPage < 1) {
            this.currentPage = 1;
        } else if (currentPage > totalPages) {
            this.currentPage = totalPages;
        } else {
            this.currentPage = currentPage;
        }
    }

    // 获取每页记录数
    public int getSize() {
        return size;
    }

    // 获取总页数
    public int getTotalPages() {
        return totalPages;
    }

    // 获取总记录数
    public int getTotal() {
        return total;
    }

    // 计算当前页的起始记录索引
    public int getStartIndex() {
        return (currentPage - 1) * size;
    }

    // 以下为示例方法，展示如何使用分页类
    public static void main(String[] args) {
        // 假设我们有100条记录，每页显示10条
        Pagination pagination = new Pagination(100, 10);

        // 打印分页信息
        System.out.println("总页数: " + pagination.getTotalPages());
        System.out.println("每页记录数: " + pagination.getSize());
        System.out.println("当前页码: " + pagination.getCurrentPage());
        System.out.println("当前页起始记录索引: " + pagination.getStartIndex());

        // 设置当前页为第5页
        pagination.setCurrentPage(5);
        System.out.println("当前页码: " + pagination.getCurrentPage());
        System.out.println("当前页起始记录索引: " + pagination.getStartIndex());
    }
}