struts分页算法

/**   
* @Title: PageBean.java 
* @Package com.salayandperformance.util 
* @Description: TODO(这个是用来action分页的javaBean) 
* @author 张兵 【390125214@qq.com】
* @date 2013-1-30 下午1:06:45 
* @version V1.0   成都大学信息科学与技术学院
*/
package com.salayandperformance.util;

/** 
 * @ClassName: PageBean 
 * @Description: TODO(这个是用来action分页的javaBean) 
 * @author 张兵 【390125214@qq.com】
 * @date 2013-1-30 下午1:06:45 
 *  
 */
public class PageBean {
    private int currentPage = 1 ;//当前页
    private int totlePages = 0;//总页数
    private int pageSize = 0;//每页显示的数据
    private int totleRows = 0;//总数据数
    private int startNum = 0 ;//开始记录（指的是数据库的offset 去掉前多少条记录）
    private int nextPage = 0;//下一页
    private int previousPage;//上一页
    private boolean hasNextPage = false ; //是否有下一页默认是false
    private boolean hasPreviousPage = false;//是否有上一页，默认为false
    //默认的构造函数
    public PageBean(){}
    /**
     * 执行分页的函数
     * @param pageSize 每页显示的数据的个数
     * @param currentPage 当前页
     * @param totalRows 数据总数
     * 
     * */
    public PageBean(int pageSize, int currentPage, int totleRows){
        this.pageSize = pageSize;
        this.currentPage = currentPage;
        this.totlePages = totleRows;
        //计算总页数
        if(totleRows%pageSize ==0){
            totlePages = totleRows/pageSize;
        }else {
            totlePages = totleRows/pageSize+1;
        }
        //当前页大于总页数，说明是最后一页
        if(currentPage>totlePages){
            hasNextPage = false;
            currentPage = totlePages;
        }else {
            hasNextPage = true;
        }
        //如果当前页小于或者等于第一页，说明是第一页
        if(currentPage<=1){
            hasPreviousPage = false;
            currentPage = 1 ;
        }else {
            hasPreviousPage = true;
        }
        //开始记录
        startNum = (currentPage - 1) * pageSize;
        //下一页
        nextPage = currentPage + 1;
        //如果下一页就是为总页数那么就是最后一页
        if(nextPage>=totlePages){
            nextPage = totlePages;
        }
        //那么上一页就是当前页的前一页，那么就-1
        previousPage = currentPage - 1;
        //如果上一页就是<=1，那么上一页就是第一页
        if(previousPage<=1){
            previousPage = 1;
        }
    }
    public int getCurrentPage() {
        return currentPage;
    }
    public void setCurrentPage(int currentPage) {
        this.currentPage = currentPage;
    }
    public int getTotlePages() {
        return totlePages;
    }
    public void setTotlePages(int totlePages) {
        this.totlePages = totlePages;
    }
    public int getPageSize() {
        return pageSize;
    }
    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }
    public int getTotleRows() {
        return totleRows;
    }
    public void setTotleRows(int totleRows) {
        this.totleRows = totleRows;
    }
    public int getStartNum() {
        return startNum;
    }
    public void setStartNum(int startNum) {
        this.startNum = startNum;
    }
    public int getNextPage() {
        return nextPage;
    }
    public void setNextPage(int nextPage) {
        this.nextPage = nextPage;
    }
    public int getPreviousPage() {
        return previousPage;
    }
    public void setPreviousPage(int previousPage) {
        this.previousPage = previousPage;
    }
    public boolean isHasNextPage() {
        return hasNextPage;
    }
    public void setHasNextPage(boolean hasNextPage) {
        this.hasNextPage = hasNextPage;
    }
    public boolean isHasPreviousPage() {
        return hasPreviousPage;
    }
    public void setHasPreviousPage(boolean hasPreviousPage) {
        this.hasPreviousPage = hasPreviousPage;
    }
}