一個通用的Java分頁基類代碼詳解
更新時間:2017年12月20日 15:07:04 作者:wgd7
這篇文章主要介紹了一個通用的Java分頁基類代碼詳解,具有一定借鑒價值,需要的朋友可以參考下。
分頁的基類
import java.util.List;
/**
* 分頁顯示的標準類,基本操作,是先給予-當前頁數一共的數據條數-每頁顯示的條數,
* 然后在初始化該類,得到總共頁數,和開始序號和結束序號,
* 然后數據庫分頁用到開始序號和結束序號,得到數據集合后賦值給該類的list屬性,
*
* 然后把該類發(fā)送到jsp頁面,進行訪問
* @author admin
*
* @param <T>
*/
public class PageBean<T> {
private int pageIndex;
//當前頁數
private int pageSize;
//一共的頁數
private int count;
//數據條數
private int pageCount;
//每頁的數據條數
private int start;
//起始數據位置
private int end;
//結束
private List<T> list=null;
public void init(){
/*根count 和pageCount計算頁數pageSize
*/
int pageSize_x=(int)count/pageCount;
if(count>=pageCount){
this.pageSize=count%pageCount==0?pageSize_x:pageSize_x+1;
} else{
this.pageSize=1;
}
//判斷頁數和當前頁數
if(pageIndex>pageSize){
pageIndex=pageSize;
}
if(pageIndex<1){
pageIndex=1;
}
//根據當前頁計算起始和結束條目
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調用
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頁面的顯示調用
<%@ 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" >下一個</a>[${pagebean.pageIndex }<span>/</span>${pagebean.pageSize}]
</body>
</html>
總結
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