Displaytag1.1支持在外部实现大数据量分页。主要有两种方式实现：
Displaytag 1.1 offers two alternative ways for working with partial lists:
- the first one uses the valuelist pattern, and requires that the object that you give to displaytag implements the org.displaytag.pagination.PaginatedList interface. You can pass this object to displaytag as an usual list, and it will extract paging and sorting information from it. This way is more recommended if you have to build your backend layer and you can easily follow this pattern.
- a second way, recommended if you only have to use partial list for few tables that show a performance problem using full lists, is passing all the needed parameters as separate tag attributes (recors to be shown, page number, total number of records...)
其中第二种方式看起来较为简单，只需在<displaytag>中增加两个属性：partialList="true"size="resultSize"即可，但是在使用发现这种方式由于是在原来内存分页的基础上修改的，所以还是存在一些Bug（比如：分页导航的值不会变......）
所以这里介绍Displaytag推荐的第一种方式，即：
实现org.displaytag.pagination.PaginatedListorg.displaytag.pagination.PaginatedList接口。
实现PaginatedList接口：
import java.util.List;
import org.displaytag.pagination.PaginatedList;
import org.displaytag.properties.SortOrderEnum;
/** */ /**
* 分页列表
*
* @author John.Zhu
*
*/
public class PageList implements PaginatedList 
{
/** */ /**
* 每页的列表
*/
private List list;
/** */ /**
* 当前页码
*/
private int pageNumber = 1 ;
/** */ /**
* 每页记录数 page size
*/
private int objectsPerPage = 15 ;
/** */ /**
* 总记录数
*/
private int fullListSize = 0 ;
private String sortCriterion;
private SortOrderEnum sortDirection;
private String searchId;
public List getList() {
return list;
}
public void setList(List list) {
this .list = list;
}
public int getPageNumber() {
return pageNumber;
}
public void setPageNumber( int pageNumber) {
this .pageNumber = pageNumber;
}
public int getObjectsPerPage() {
return objectsPerPage;
}
public void setObjectsPerPage( int objectsPerPage) {
this .objectsPerPage = objectsPerPage;
}
public int getFullListSize() {
return fullListSize;
}
public void setFullListSize( int fullListSize) {
this .fullListSize = fullListSize;
}
public String getSortCriterion() {
return sortCriterion;
}
public void setSortCriterion(String sortCriterion) {
this .sortCriterion = sortCriterion;
}
public SortOrderEnum getSortDirection() {
return sortDirection;
}
public void setSortDirection(SortOrderEnum sortDirection) {
this .sortDirection = sortDirection;
}
public String getSearchId() {
return searchId;
}
public void setSearchId(String searchId) {
this .searchId = searchId;
}
}
/** */ /**
* 分页查询
*
* @param request
* @param response
* @return
* @throws Exception
*/
private ModelAndView paging(HttpServletRequest request,
HttpServletResponse response, ModelAndView mav) throws Exception {
// 获取当前页数，displaytag通过参数"page"传递这个值
int pageNumber;
if (request.getParameter( " page " ) != null
&& ! "" .equals(request.getParameter( " page " ))) {
pageNumber = Integer.parseInt(request.getParameter( " page " ));
} else {
pageNumber = 1 ;
}
PageList pageList = new PageList();
Map map = WebUtils.getParametersStartingWith(request, " search_ " );
Page page = dao.query(map, pageNumber, PAGE_SIZE);
// 设置当前页数
pageList.setPageNumber(pageNumber);
// 设置当前页列表
pageList.setList(page.getResults());
// 设置page size
pageList.setObjectsPerPage(PAGE_SIZE);
// 设置总页数
pageList.setFullListSize(page.getTotalCount());
mav.addObject( " results " , pageList);
return mav;
}
好了，现在直接在JSP上使用 displaytag就行了：
< display:table name ="${results}" id ="row" class ="simple nocol" pagesize ="${pageSize}" export ="true"
decorator ="org.displaytag.decorator.TotalTableDecorator"
requestURI ="${pageContext.request.contextPath}/pageQuery.do?method=paging" >
< display:column property ="date.time" title ="日期" format ="{0,date,yyyy-MM-dd}" sortable ="false" />
< display:column property ="code" title ="编码" group ="1" sortable ="false" />
< display:column property ="name" title ="名称" group ="1" sortable ="false" />
< display:column property ="costTotal" title ="总额(元)" format ="{0,number,0,000}" total ="true" sortable ="false" />
</ display:table >
本文转自:http://www.blogjava.net/zJun/archive/2007/02/08/98703.html
posted on 2007-09-15 10:21
Ke 阅读(1669)
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