一个通用的Java分页基类代码详解

2024-07-13 10:15:05

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分页的基类

java/92761.html">java;">import java.util.List;/** * 分页显示的标准类,基本操作,是先给予-当前页数一共的数据条数-每页显示的条数, * 然后在初始化该类,得到总共页数,和开始序号和结束序号, * 然后数据库分页用到开始序号和结束序号,得到数据集合后赋值给该类的list属性, *  * 然后把该类发送到jsp页面,进行访问 * @author admin * * @param <T> */public class PageBean<T> {	private int pageIndex;	//当前页数	private int pageSize;	//一共的页数	private int count;	//数据条数	private int pageCount;	//每页的数据条数	private int start;	//起始数据位置	private int end;	//结束	private List<T> list=null;	public void init(){		/*根count 和pageCount计算页数pageSize     */		int pageSize_x=(int)count/pageCount;		if(count>=pageCount){			this.pageSize=count%pageCount==0?pageSize_x:pageSize_x+1;		} else{			this.pageSize=1;		}		//判断页数和当前页数		if(pageIndex>pageSize){			pageIndex=pageSize;		}		if(pageIndex<1){			pageIndex=1;		}		//根据当前页计算起始和结束条目		this.start=(pageIndex-1)*pageCount+1;		this.end=pageIndex*pageCount;	}	public PageBean(int pageIndex, int count, int pageCount) {		super();		this.pageIndex = pageIndex;		this.count = count;		this.pageCount = pageCount;	}	public PageBean(int pageIndex, int count, int pageCount, List<T> list) {		super();		this.pageIndex = pageIndex;		this.count = count;		this.pageCount = pageCount;		this.list = list;	}	public PageBean() {		super();		// TODO Auto-generated constructor stub	}	@Override	  public String toString() {		return "PageBean [count=" + count + ", end=" + end + ", list=" + list		        + ", pageCount=" + pageCount + ", pageIndex=" + pageIndex		        + ", pageSize=" + pageSize + ", start=" + start + "]";	}	public int getPageIndex() {		return pageIndex;	}	public void setPageIndex(int pageIndex) {		this.pageIndex = pageIndex;	}	public int getPageSize() {		return pageSize;	}	public void setPageSize(int pageSize) {		this.pageSize = pageSize;	}	public int getCount() {		return count;	}	public void setCount(int count) {		this.count = count;	}	public int getPageCount() {		return pageCount;	}	public void setPageCount(int pageCount) {		this.pageCount = pageCount;	}	public int getStart() {		return start;	}	public void setStart(int start) {		this.start = start;	}	public int getEnd() {		return end;	}	public void setEnd(int end) {		this.end = end;	}	public List<T> getList() {		return list;	}	public void setList(List<T> list) {		this.list = list;	}}

servlet调用

import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.dao.MessageDao;import com.dao.impl.MessageDaoImpl;import com.vo.Message;import com.vo.PageBean;public class ShowMessageServlet extends HttpServlet{	/**   *    */	private static final long serialVersionUID = 6646899131087204214L;	@Override	  protected void doPost(HttpServletRequest req, HttpServletResponse resp)	      throws ServletException, IOException {		doGet(req, resp);	}	@Override	  protected void doGet(HttpServletRequest req, HttpServletResponse resp)	      throws ServletException, IOException {		req.setCharacterEncoding("UTF-8");		resp.setContentType("text/html;charset=utf-8");		int pageIndex=0;		MessageDao md=new MessageDaoImpl();		String pageIndexStr=req.getParameter("pageIndex");		if(pageIndexStr!=null){			try{				pageIndex=Integer.parseint(pageIndexStr);			}			catch (Exception e) {			}		}		PageBean<Message> pb=new PageBean<Message>(pageIndex,md.getMessageCount(),10);		pb.init();		pb.setList(md.getMessageListOfPage(pb.getStart(), pb.getEnd()));		req.setAttribute("pagebean", pb);		req.getRequestDispatcher("index.jsp").forward(req, resp);	}}

jsp页面的显示调用

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html> <head>  <base href="<%=basePath%>" rel="external nofollow" >  <title>My JSP 'index.jsp' starting page</title>  <meta http-equiv="pragma" content="no-cache">  <meta http-equiv="cache-control" content="no-cache">  <meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">  <meta http-equiv="description" content="This is my page">  <!--  <link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" >  --> </head> <c:if test="${empty pagebean}">  <jsp:forward page="showmessage"></jsp:forward> </c:if> <body>  <c:forEach var="message" items="${pagebean.list}">    ${message.title }  ${message.editdate }<br/>  </c:forEach>  <a href="showmessage?pageIndex=${pagebean.pageIndex+1}" rel="external nofollow" >下一个</a>[${pagebean.pageIndex }<span>/</span>${pagebean.pageSize}] </body></html>

总结

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