Struts+hibernate分页显示（资料二）[Pager类]

package com.jpcf.db.helper;

import java.math.*;

public class Pager {
private int totalRows; //总行数
private int pageSize = 10; //每页显示的行数
private int currentPage; //当前页号
private int totalPages; //总页数
private int startRow; //当前页在数据库中的起始行

public Pager() {
}

public Pager(int _totalRows) {//总行数作为传入参数
totalRows = _totalRows;
totalPages=totalRows/pageSize;
int mod=totalRows%pageSize;
if(mod>0){
totalPages++;
}//计算总页数
currentPage = 1;
startRow = 0;
}

public int getStartRow() {
return startRow;
}

public int getTotalPages() {
return totalPages;
}

public int getCurrentPage() {
return currentPage;
}

public int getPageSize() {
return pageSize;
}

public void setTotalRows(int totalRows) {
this.totalRows = totalRows;
}

public void setStartRow(int startRow) {
this.startRow = startRow;
}

public void setTotalPages(int totalPages) {
this.totalPages = totalPages;
}

public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}

public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}

public int getTotalRows() {
return totalRows;
}

public void first() { //回首页
currentPage = 1;
startRow = 0;
}

public void previous() {//上一页
if (currentPage == 1) {
return;
}
currentPage--;
startRow = (currentPage - 1) * pageSize;
}

public void next() {//下一页
if (currentPage < totalPages) {
currentPage++;
}
startRow = (currentPage -1) * pageSize;
}

public void last() {//最后一页
currentPage = totalPages;
startRow = (currentPage - 1) * pageSize;
}

public void refresh(int _currentPage) {
currentPage = _currentPage;
if (currentPage > totalPages) {
last();
}
}

}

 /*

 * @(#)Pager.java    2005-5-3

 *

 * Copyright (c) 2005, Jeffrey Hsu

 */

package com.jeffrey.messagelove;

/**

 *  Pager holds the page info.

 */

public class Pager {

    private int totalRows = 0; // 记录总数

    private int totalPages = 0; // 总页数

    private int pageSize = 10; // 每页显示数据条数，默认为10条记录

    private int currentPage = 1; // 当前页数

    private boolean hasPrevious = false; // 是否有上一页

    private boolean hasNext = false; // 是否有下一页

    public Pager() {

    }

    /**

     * Initialize Pager

     * @param totalRows total record rows

     * @param pageSize total record is hold by every page

     */

    public void init(int totalRows, int pageSize) {

        this.totalRows = totalRows;

        this.pageSize = pageSize;

        totalPages = ((totalRows + pageSize) - 1) / pageSize;

        refresh(); // 刷新当前页面信息

    }

    /**

     * @return Returns the currentPage.

     */

    public int getCurrentPage() {

        return currentPage;

    }

    /**

     * @param currentPage current page

     */

    public void setCurrentPage(int currentPage) {

        this.currentPage = currentPage;

        refresh();

    }

    /**

     * @return Returns the pageSize.

     */

    public int getPageSize() {

        return pageSize;

    }

    /**

     * @param pageSize The pageSize to set.

     */

    public void setPageSize(int pageSize) {

        this.pageSize = pageSize;

        refresh();

    }

    /**

     * @return Returns the totalPages.

     */

    public int getTotalPages() {

        return totalPages;

    }

    /**

     * @param totalPages The totalPages to set.

     */

    public void setTotalPages(int totalPages) {

        this.totalPages = totalPages;

        refresh();

    }

    /**

     * @return Returns the totalRows.

     */

    public int getTotalRows() {

        return totalRows;

    }

    /**

     * @param totalRows The totalRows to set.

     */

    public void setTotalRows(int totalRows) {

        this.totalRows = totalRows;

        refresh();

    }

       // 跳到第一页

    public void first() {

        currentPage = 1;

        this.setHasPrevious(false);

        refresh();

    }

       // 取得上一页（重新设定当前页面即可）

    public void previous() {

        currentPage--;

        refresh();

    }

       // 取得下一页

    public void next() {

        System.out.println("next: totalPages: " + totalPages +

            " currentPage : " + currentPage);

        if (currentPage < totalPages) {

            currentPage++;

        }

        refresh();

    }

       // 跳到最后一页

    public void last() {

        currentPage = totalPages;

        this.setHasNext(false);

        refresh();

    }

    public boolean isHasNext() {

        return hasNext;

    }

    /**

     * @param hasNext The hasNext to set.

     */

    public void setHasNext(boolean hasNext) {

        this.hasNext = hasNext;

    }

    public boolean isHasPrevious() {

        return hasPrevious;

    }

    /**

     * @param hasPrevious The hasPrevious to set.

     */

    public void setHasPrevious(boolean hasPrevious) {

        this.hasPrevious = hasPrevious;

    }

       // 刷新当前页面信息

    public void refresh() {

        if (totalPages <= 1) {

            hasPrevious = false;

            hasNext = false;

        } else if (currentPage == 1) {

            hasPrevious = false;

            hasNext = true;

        } else if (currentPage == totalPages) {

            hasPrevious = true;

            hasNext = false;

        } else {

            hasPrevious = true;

            hasNext = true;

        }

    }

}