Action做分页

1.Pager类 分页公共类功能：Pager类用于计算首页、前一页、下一页、尾页的在数据库中的起始行，当前的页码。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) totalRows = _totalRows; totalPages=totalRows/pageSize; int mod=totalRows%pageSize; if(mod0) totalPages+; 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() /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) last(); 2.PagerHelp类 功能：PageHelper这个类，用于从页面上取得参数进行相应的业务逻辑处理package com.jpcf.db.helper;import javax.servlet.http.*;public class PagerHelper public static Pager getPager(HttpServletRequest httpServletRequest, int totalRows) /定义pager对象，用于传到页面 Pager pager = new Pager(totalRows); /从Request对象中获取当前页号 String currentPage=httpServletRequest.getParameter(currentPage); /如果当前页号为空，表示为首次查询该页 /如果不为空，则刷新pager对象，输入当前页号等信息 if (currentPage != null) pager.refresh(Integer.parseInt(currentPage); /获取当前执行的方法，首页，前一页，后一页，尾页。 String pagerMethod = httpServletRequest.getParameter(pageMethod); if (pagerMethod != null) if (pagerMethod.equals(first) pager.first(); elseif (pagerMethod.equals(previous)pager.previous(); else if (pagerMethod.equals(next)pager.next(); else if (pagerMethod.equals(last) pager.last();return pager; 3.部门DAO类中的方法 功能说明：利用hibernate中的 setFirstResult(parma)和.setMaxResults(parma)进行分页上线和下线的约束 /* * param pageSize 每页显示几条数据; * param startRow 从数据库哪条数据开始显示 */public List findWithPage(int startRow,int pageSize) List list = null;try list=getSession().createQuery(from Users).setFirstResult(startRow).setMaxResults(pageSize).list();System.out.println(list); catch (RuntimeException re) throw re ;return list;/* * 统计数据库中的记录 */public int getRows() int totalRows = 0;try getSession().getTransaction().begin();/查询语句select count(*) from VehicleProperty 也可以换成你需要的任意的条件(select count(*) from VehicleProperty where .)long number= (Long)getSession().createQuery(select count(*) from VehicleProperty).uniqueResult();totalRows=(int)number;getSession().getTransaction().commit(); catch (RuntimeException re) re.printStackTrace();getSession().getTransaction().rollback();throw re;return totalRows;4.Action 下面是在Action中用到的代码： public void findWithPage(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException int totalRows;/记录总行数 totalRows=dao.getRows(); try /通过PagerHelper类来获取用于输出到页面的pager对象 Pager pager=PagerHelper.getPager(request,totalRows); List list=(List)dao.findWithPage( pager.getStartRow(),pager.getPageSize(); request.setAttribute(list, list); request.setAttribute(totalPage, pager.getTotalPages(); request.setAttribute(currentPage, pager.getCurrentPage(); request.getRequestDispatcher(/jsp/view.jsp).forward(request, response); catch (Exception e) e.printStackTrace(); response.sendRedirect(request.getContextPath(