分页查询

page 类代码分页查询代码

package com.pb.pager;

public class Pager {
    /**
     * 总页数
     */
    private int totalcount = 0;
    /**
     * 页面大小，即每页显示记录数
     */
    private int pageSize = 0;
    /**
     * 记录总数
     */
    private int recordCount = 0;
    
    /**
     * 当前页号
     */
    private int currPageNo=0;

    public int getCurrPageNo() {
        if(totalcount==0)
            return 0;
        return currPageNo;
    }

    public void setCurrPageNo(int currPageNo) {
        if(currPageNo>0)
        this.currPageNo = currPageNo;
    }

    public int getTotalcount() {
        return totalcount;
    }

    public void setTotalcount(int totalcount) {
        this.totalcount = totalcount;
    }

    public int getPageSize() {
        return pageSize;
    }

    public void setPageSize(int pageSize) {
        if (pageSize > 0)
            this.pageSize = pageSize;
    }

    public int getRecordCount() {
        return recordCount;
    }

    public void setRecordCount(int recordCount) {
        if (recordCount > 0)
            this.recordCount = recordCount;
    }

    // 设置总页数
    private void setTotalpagecount() {
        if (this.recordCount % this.pageSize == 0) {
            this.recordCount = this.recordCount / this.pageSize;
        } else if (this.recordCount % this.pageSize > 0) {
            this.recordCount = this.recordCount / this.pageSize + 1;
        }else{            
            this.recordCount=0;
        }    
    }
    /**
     * 开始记录数
     * @return
     */
    public int getStartRow(){
        return (currPageNo-1)*pageSize+1;
        
    }
    /**
     * 结束记录数
     * @return
     */
    public int getEndRow(){
        return currPageNo*pageSize;
        
    }
}

分页查询的步骤

（1）.确定每页显示的数据数量

（2）.计算显示数据的总数量

（3）.计算显示的页数=总数量/每页显示的数据数量（+1）

（4）。编写分页查询SQl语句

（5）.实现分页查询

使用CallbleStatement执行存储过程

    public int getTotalcountProc() {
        int totalCount=0;
        CallableStatement proc=null;
        String sql="{call PRO_GETTOTALCOUNT(?)}";
        getConnection();
        try {
            proc=con.prepareCall(sql);
            proc.registerOutParameter(1, Types.INTEGER);
            proc.execute();
            totalCount=proc.getInt(1);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        // TODO Auto-generated method stub
        return totalCount;
    }

分页显示关键点

确定当前页

设置首页，上一页，下一页，末页的页码

首页和末页的控制

<script type="text/javascript">
function page_nav(frm,num){
        frm.pageIndex.value=num;
        frm.submit();
    }
    function jump_to(frm,pegeno){
        var regexp=/^\d+$/;
        if(!regexp.test(pegeno)){
            alert("请输入正确数字！");
            return false;
        }else{
            page_nav(frm,pegeno);
        }
        
    }
</script>
 <%
                //获取当前页码
                String currentPage=request.getParameter("pageIndex");
                if(currentPage==null)
                    currentPage="1";
                int pageIndex=Integer.parseInt(currentPage);
                //获取新闻记录总数量   
                int total=newsService.getTotalcount();
                //每页显示记录数
                int pagesize=2;
                /*获取总页数*/
                Pager pag=new Pager();
                pag.setCurrPageNo(pageIndex);
                pag.setPageSize(pagesize); 
                pag.setRecordCount(total);
                int totalpage=pag.getTotalPagecount();
                //控制首页和末页
                if(pageIndex<1){
                    pageIndex=1;
                }else if(pageIndex>totalpage){                  
                    pageIndex=totalpage;
                }
                
                List<News> newsList=newsService.getPageNewsList(pageIndex,pagesize);
%>
    <li>共<%=total%>条记录&nbsp;&nbsp;<%=currentPage%>/<%=totalpage %>页</li>
                <%
                if(pageIndex>1){
                %>
                <a href="javascript:page_nav(document.forms[0],1)">首页</a>&nbsp;&nbsp;
                <a href="javascript:page_nav(document.forms[0],<%=pageIndex-1%>)">上一页</a>&nbsp;&nbsp;
                <%
                    }if(pageIndex<totalpage){
                %>
                <a href="javascript:page_nav(document.forms[0],<%=pageIndex+1%>)">下一页</a>&nbsp;&nbsp;
                <a href="javascript:page_nav(document.forms[0],<%=totalpage %>) ">最后一页</a>&nbsp;&nbsp;
                <%
                }
                %>

表单隐藏域传递代码

<script type="text/javascript">
    function page_nav(frm,num){
        frm.pageIndex.value=num;
        frm.submit();
    }//go跳转函数
    function jump_to(frm,pegeno){
        var regexp=/^\d+$/;
        if(!regexp.test(pegeno)){
            alert("请输入正确数字！");
            return false;
        }else{
            page_nav(frm,pegeno);
        }
        
    }
</script>
 <form name ="searchForm" id="searchForm" action="/JDBC1/jsp/admin/newsDetailList.jsp" method="post">
<input type="hidden" name="pageIndex" value="1"/>
</form>
<%
                if(pageIndex>1){
                %>
                <a href="javascript:page_nav(document.forms[0],1)">首页</a>&nbsp;&nbsp;
                <a href="javascript:page_nav(document.forms[0],<%=pageIndex-1%>)">上一页</a>&nbsp;&nbsp;
                <%
                    }if(pageIndex<totalpage){
                %>
                <a href="javascript:page_nav(document.forms[0],<%=pageIndex+1%>)">下一页</a>&nbsp;&nbsp;
                <a href="javascript:page_nav(document.forms[0],<%=totalpage %>) ">最后一页</a>&nbsp;&nbsp;
                <%
                }
                %>
 <span class="page-go-form"><label>跳转至</label>
      <input type="text" name="inputPage" id="inputPage" class="page-key" />页
      <button type="button" class="page-btn" onClick='jump_to(document.forms[0],document.getElementById("inputPage").value)'>GO</button>
  </span>

注意当页面404错误时检查路径是否正确；