关于分页前台页面+后台实现

package com.entity;

/**
 * 分页工具类
 * 
 * @author H.ros
 *
 */
public class PageUtils {
    // 当前页默认第1页（从页面获取的当前页码，未计算）
    private int currentPage = 1;
    // 前一页
    private int prevPage;
    // 下一页
    private int nextPage;
    // 尾页
    private int lastPage;
    // 总记录数
    private int count;
    // 每页的条数,默认10条
    private int pageSize = 1;
    // 开始记录数，分页计入数（使用时调用的初始页，计算后）
    private int pageRecord;
    // 页面分页html模型代码
    private String page;

    // 有参构造器
    public PageUtils(String currentPage, int count, String pageSize) {
        init(currentPage, count, pageSize);
        initLastPage();
        initCurrentPage();
        initPrevPage();
        initNextPage();
        initPageRecord();
        initPage();
    }

    // 初始化三个重要元素
    private void init(String currentPage, int count, String pageSize) {
        if (currentPage != null && currentPage != "" && currentPage != "0") {
            this.currentPage = Integer.parseInt(currentPage);
        }

        this.count = count;

        if (pageSize != null && pageSize != "" && pageSize != "0") {
            this.pageSize = Integer.parseInt(pageSize);
            ;
        }
    }

    // 初始化尾页
    private void initLastPage() {
        if (count % pageSize == 0) {
            lastPage = count / pageSize;
        } else {
            lastPage = count / pageSize + 1;
        }
    }

    // 初始化并矫正当前页(防止外部访问出错)
    private void initCurrentPage() {
        if (currentPage < 1) {
            currentPage = 1;
        } else if (currentPage > lastPage) {
            currentPage = lastPage;
        }
    }

    // 初始化上一页
    private void initPrevPage() {
        if (currentPage != 1) {
            prevPage = currentPage - 1;
        } else {
            prevPage = 1;
        }
    }

    // 初始化下一页
    private void initNextPage() {
        if (currentPage != lastPage) {
            nextPage = currentPage + 1;
        } else {
            nextPage = lastPage;
        }
    }

    // 初始化分页计入数
    private void initPageRecord() {
        pageRecord = (currentPage - 1) * pageSize;
        if (pageRecord < 0) {
            pageRecord = 0;
        }
    }

    // 初始化html页面分页模型代码
    private void initPage() {
        page = "<div style=‘text-align: right;‘>";
        page += "第" + currentPage + "/" + lastPage + "页，共" + count + "条记录。";
        page += "<select style=‘width: 70px;‘ id=‘pageSize‘ onchange=‘page(1)‘><option>1</option><option>2</option><option>5</option></select>";
        page += "<input type=‘button‘ value=‘首页‘ onclick=‘page(1)‘ />";
        page += "<input type=‘button‘ value=‘上一页‘ onclick=‘page(" + prevPage + ")‘ />";
        page += "<input type=‘button‘ value=‘下一页‘ onclick=‘page(" + nextPage + ")‘ />";
        page += "<input type=‘button‘ value=‘尾页‘ onclick=‘page(" + lastPage + ")‘ />";
        page += "</div>";
    }

    /*
     * 对外访问通道
     */
    public int getCurrentPage() {
        return currentPage;
    }

    public int getPrevPage() {
        return prevPage;
    }

    public int getNextPage() {
        return nextPage;
    }

    public int getLastPage() {
        return lastPage;
    }

    public int getCount() {
        return count;
    }

    public int getPageSize() {
        return pageSize;
    }

    public int getPageRecord() {
        return pageRecord;
    }

    public String getPage() {
        return page;
    }

}

查询语句中
    int count = bannerService.selectCount();
        PageUtils pageUtils = new PageUtils(currentPage, count, pageSize);
        // 开始记录数,由工具类中计算得出
        int begin = pageUtils.getPageRecord();
        // 查几条记录
        int number = pageUtils.getPageSize();
        // 前台页面分页模型（传入页面使用的html代码）
        String page = pageUtils.getPage();
        List<Banner2> list = bannerService.selectAll(begin, number);

        map.put("banner", list);
        map.put("page", page);
        map.put("number", number);

 <select id="selectAll" resultMap="BaseResultMap" >
 
    select * from banner limit ${begin},${number}
  </select>
  
  <select id="selectCount" resultType="int">
  select count(*) count from banner
  </select>

$(function(){
    $("#pageSize").val("${number}");
})
function page(i){
    //获取到下拉框选中的值
    var pageSize = $("#pageSize").find("option:selected").text()
    window.location.href="/ShoppingBackstage/banner/indexs?currentPage="+i+"&pageSize="+pageSize+" "
}

${page}

public interface bannerService {
    public List<Banner2> selectAll(int begin, int number);

    public int selectCount();

    public void insert(Banner2 banner);

    public void delete(int id);

    public void update(Banner2 banner2);

    public Banner2 selectByid(int id);

}