一个通用的Java分页基类代码详解
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2023-12-14 22:44:04
分页的基类
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,
*...
分页的基类
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>
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