直接用List对象进行分页

最新推荐文章于 2022-08-02 08:00:00 发布

原创最新推荐文章于 2022-08-02 08:00:00 发布 · 1.5k 阅读

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CC 4.0 BY-SA版权

文章标签：

#list #javascript #function #hibernate #class #input

本文介绍了一种避免每次页码变化时都查询数据库的分页方法，通过在前端直接对查询结果进行分页，提高效率。文章提供了一组JavaScript函数来处理分页操作，并展示了Action和DAO页面如何配合实现这一逻辑。

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传统的Spring和Hibernate分页，可能使访问不断继续，如果数据量太大，请求过程就会很大，笔者认为，如果改变思路，直接对查询后返回的结果进行分页，这样就不必每次进行页码变化时，都对数据库进行请求，效率大大提高！

但是同时相应的逻辑也变得稍微复杂了，只要把握好业务逻辑，就能进行快速开发！

以下是代码,和大家一起分享：

jsp页面:
<script type="text/javascript">
function pageFirst(count){
    var currentPage = count;
          if(currentPage >= 1)
            {
           document.getElementById("pagination").currentPage.value = 1;
           document.getElementById("pagination").submit();
             }
  }

  function pageFront(count){
   var currentPage = count;
           if(currentPage >=1)
             {
    document.getElementById("pagination").currentPage.value = count;
    document.getElementById("pagination").submit();
    }
     else
      {
        return;
      }
  }

  function pageNext(count){
  var currentPage =count;
  var totalPage =${totalPage};

    if(currentPage < totalPage)
     {
       document.getElementById("pagination").currentPage.value =count;
     document.getElementById("pagination").submit();
   }
     else
      {
        return;
     }
  }

  function pageLast(count){
  var currentPage = count;
    var totalPage = ${totalPage};
   if(currentPage <= totalPage)
     {
      document.getElementById("pagination").currentPage.value =totalPage;
      document.getElementById("pagination").submit();
   }
  }
  function toPage(count){
  var currentPage = count;
    var totalPage = ${totalPage};
    if(currentPage > totalPage)
     {
     document.getElementById("pagination").currentPage.value=totalPage;
     }
     if(currentPage<1){
     document.getElementById("pagination").currentPage.value=1;
     }
    document.getElementById("pagination").submit();
  }
  </script>
<html:form action="/dinner/findHotel.do?method=findMorePassagesAboutRes" method="post" styleId="pagination">
<html:hidden property="totalPage"/>
<html:hidden property="maxRecord"/>
<table width="95%" border="0" align="center" cellpadding="3"
cellspacing="0" class="table3">
<tr>
<td align="right" class="bianju_in">
<div class="body">
[
<a href="javascript:pageFirst(1);">第一页</a>] [
<a href="javascript:pageFront(${currentPage-1});">上一页</a>]｜
[
<a href="javascript:pageNext(${currentPage+1});">下一页</a>]
[
<a href="javascript:pageLast(${totalPage});">最后一页</a>]  
第
<input name="currentPage" id="currentPage" size="2" value="${currentPage}"/>页
<input type="hidden" name="maxRecord"
value="${maxRecord}" />
<input type="button" value=">>"
                      onClick="javascript:toPage(document.getElementById('currentPage').value)" />
共 ${totalPage} 页 
  </div>
</td>
</tr>
</table>
</html:form>
Action页面:
public ActionForward findList(ActionMapping mapping,ActionForm form,HttpservletRequest request,HttpServletresponse response){
TBRestaurantActionForm restaurantForm=(TBRestaurantActionForm)form;
request.setAttribute("recommend",dealWithLeaf(restaurantForm,recommend));
request.setAttribute("totalPage", restaurantForm.getTotalPage());
request.setAttribute("maxRecord",restaurantForm.getMaxRecord());
request.setAttribute("currentPage", restaurantForm.getCurrentPage());
}
public List dealWithLeaf(RestaurantActionForm form,List list){
    RestaurantActionForm myform=(RestaurantActionForm)form;
    long maxRecord=myform.getMaxRecord();
    if(maxRecord%FETCHSIZE==0){       //刚好均匀分配
     myform.setTotalPage((int)(maxRecord/FETCHSIZE));
    return getFetchSizeByPageNo(myform.getCurrentPage(),list);
     }
    else{
     myform.setTotalPage((int)(maxRecord/FETCHSIZE)+1);
     List newlist=new ArrayList();
     if(myform.getCurrentPage()<myform.getTotalPage()){
    for (int i =(myform.getCurrentPage()-1)*FETCHSIZE; i <=myform.getCurrentPage()*FETCHSIZE-1 ; i++) {
       newlist.add(list.get(i));
    }
     }
     else{
    for (int i = (myform.getCurrentPage()-1)*FETCHSIZE; i <maxRecord; i++) {
       newlist.add(list.get(i));
    }
     }
     return newlist;
      }
}
public List getFetchSizeByPageNo(int currentPage,List list){
  List newlist=new ArrayList();
  for (int i =(currentPage-1)*FETCHSIZE; i <currentPage*FETCHSIZE-1; i++) {
     newlist.add(i,list.get(i));
  }
  return newlist;
}