說明：分頁技術分爲真分頁和假分頁，具體採用哪種技術需要根據需求自我抉擇。其實兩者之間實現區別並不是太大。在分頁之前我們需要搞明白對誰進行分頁，一般情況是將數據封裝到一個list集合中，明白這這一點問題基本上就已經解決了。（編寫匆促如有錯誤請聯繫我）
下面首先介紹真分頁。
方法一：
爲了大家學習起來方便， 我將在項目中用到的內容都放在這個文檔中，所以可能會比較蘿莉囉嗦。
1.構建數表，字段如下
| goods | |
| goodid | int |
| goodname | varchar(45) |
| price | flaot |
2，建立實體類
privateintgoodsid;//物品編號 private String goodsname; privatefloatprice;//單價 //省略getXXX,與setXXX方法
3，編寫utils工具類，實現數據庫的連接（該工具類比較粗糙，沒有借鑑的價值，之方便學習分頁使用）
publicclass DbConnection {
privatestatic Connection conn=null;
private String driver="com.mysql.jdbc.Driver";
private String url="jdbc:mysql://localhost:3306/mydata";
private String user="root";
private String password="123";
private DbConnection()
{
try {
Class.forName(driver);
conn=DriverManager.getConnection(url,user,password);
} catch(ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e){
e.printStackTrace();
}
}
publicstatic ConnectiongetConnection()
{
if(conn==null)
new DbConnection();
returnconn;
}
}
4，編寫DAO層
publicclass Dao {
privatestatic Connection conn;
privatestatic ResultSet rs=null;
privatestatic Statement stmt,stmt1;
privatestaticintpagesize=5;
static {
conn=DbConnection.getConnection();
}
publicstatic ResultSetExecuteQuery(String sql)
{
try {
stmt=conn.createStatement();
rs=stmt.executeQuery(sql);
} catch (SQLException e){
e.printStackTrace();
}
returnrs;
}
//分頁邏輯
publicstatic ArrayList<Goods> getGoodsList(int currentpageno) throws SQLException
{
ArrayList<Goods>GoodsList=newArrayList<Goods>();
int BeginRecord=(currentpageno-1)*pagesize;
int EndRecord=pagesize;//備註，注意，該處表示的是從BeginRecord開始查詢幾個數據，而不代表結束的位置。
rs=ExecuteQuery("select *from goods limit "+BeginRecord+","+EndRecord);
try {
while(rs.next())
{
Goodsgoods=new Goods();
goods.setGoodsid(rs.getInt(1));
goods.setGoodsname(rs.getString(2));
goods.setPrice(rs.getFloat(3));
GoodsList.add(goods);
}
} catch (SQLException e){
e.printStackTrace();
}
return GoodsList;
}
//返回總頁數
publicstaticint getPageCount()
{
int total=0;
int PageCount=0;
try {
rs=stmt.executeQuery("selectcount(*) from goods");
if(rs.next())
{
total=rs.getInt(1);
PageCount=(total-1)/pagesize+1;
}
} catch (SQLException e){
e.printStackTrace();
}
return PageCount;
}
}
5，servlet層
publicvoiddoPost(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException {
Stringpageno=request.getParameter("currentpageno");
int currentpageno=1;
if(pageno!=null){
currentpageno=Integer.parseInt(pageno);
}
ArrayList<Goods>GoodsList=null;
try {
GoodsList = Dao.getGoodsList(currentpageno);
System.out.println(GoodsList.size());
} catch (SQLException e){
e.printStackTrace();
}
request.setAttribute("GoodsList", GoodsList);
request.setAttribute("currentpageno", currentpageno);
request.setAttribute("PageCount",Dao.getPageCount());//設置總共頁數
request.getRequestDispatcher("/LimiteGoods.jsp").forward(request, response);
}6，jsp表示層
<%@ pagelanguage="java"contentType="text/html;charset=UTF-8" pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE htmlPUBLIC "-//W3C//DTDHTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title>分頁技術Demo</title>
<script type="text/javascript">
function jumptopage()
{
var inputnode=document.getElementById("jumptopage");
var page=inputnode.value;
if(isNaN(page))
{
alert("請輸入正整數");
}
else if(page>${PageCount})
return;
else
{
window.location="/Mypage/servlet/GetLimiteGoods?currentpageno="+page;
}
}
</script>
</head>
<body>
<center>
<table width="80%" border="1" height="56">
<tr align="center">
<td>
商品編號
</td>
<td>
商品名稱
</td>
<td>
商品價格
</td>
</tr>
<c:forEach var="goods" items="${GoodsList}">
<tr align="center">
<td>
${goods.goodsid}
</td>
<td>
${goods.goodsname}
</td>
<td>
${goods.price}
</td>
</tr>
</c:forEach>
</table>
<c:if test="${currentpageno>1}">
<a href="/Mypage/servlet/GetLimiteGoods?currentpageno=1">首頁</a>
<a href="/Mypage/servlet/GetLimiteGoods?currentpageno=${currentpageno-1}">上一頁</a>
</c:if>
<font color="blue">當前爲 ${currentpageno}頁</font>
<c:if test="${PageCount>currentpageno}">
<a href="/Mypage/servlet/GetLimiteGoods?currentpageno=${currentpageno+1}">下一頁</a>
<a href="/Mypage/servlet/GetLimiteGoods?currentpageno=${PageCount}">尾頁</a>
</c:if>
跳轉到第<input type="text" id="jumptopage" style="width:15px;">頁
<input type="button" value="go" onclick="jumptopage()">
</center>
</body>
</html>
真分頁部分結束
第二部分，假分頁的實現
1，數據表，Bean，util與第一部分相同，不再重複
2，dao層做稍微的修改
publicstatic ArrayList<Goods> getGoodsList(int currentpageno) throws SQLException
{
ArrayList<Goods>GoodsList=newArrayList<Goods>();
rs=ExecuteQuery("select * from goods");//改變的地方
try {
while(rs.next())
{
Goodsgoods=new Goods();
goods.setGoodsid(rs.getInt(1));
goods.setGoodsname(rs.getString(2));
goods.setPrice(rs.getFloat(3));
GoodsList.add(goods);
}
} catch (SQLException e){
e.printStackTrace();
}
return GoodsList;
}Dao層返回頁數部分函數不再需要
3,servlet層部分修改
publicvoiddoPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException,IOException {
int pagesize=5;//增加項
int pageCount;//增加項
Stringpageno=request.getParameter("currentpageno");
int currentpageno=1;
if(pageno!=null){
currentpageno=Integer.parseInt(pageno);
}
ArrayList<Goods>GoodsList=null;
ArrayList<Goods>gl=newArrayList<Goods>();//增加項
try {
GoodsList = Dao.getGoodsList(currentpageno);
Iterator<Goods>it=GoodsList.iterator();
//---------------------------------修改部分
int i=0;
for(i=0;i<(currentpageno-1)*5;i++)
it.next();
for(i=0;i<5;i++)
{
gl.add((Goods)it.next());
}
//---------------------------------修改部分
} catch (SQLException e){
e.printStackTrace();
}
pageCount=(GoodsList.size()-1)/pagesize+1;
request.setAttribute("GoodsList", gl);//修改部分
request.setAttribute("currentpageno", currentpageno);
request.setAttribute("PageCount",pageCount );
request.getRequestDispatcher("/LimiteGoods.jsp").forward(request,response);
}
4,jsp層和上文相同，不再重複。
5，另附web.xml文件
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns="http://java.sun.com/xml/ns/javaee"xsi:schemaLocation="http://java.sun.com/xml/ns/javaeehttp://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID"version="2.5"> <display-name>Mypage</display-name> <servlet> <servlet-name>GetLimiteGoods</servlet-name> <servlet-class>servlet.GetLimiteGoods</servlet-class> </servlet> <servlet-mapping> <servlet-name>GetLimiteGoods</servlet-name> <url-pattern>/servlet/GetLimiteGoods</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>servlet/GetLimiteGoods</welcome-file> <welcome-file>servlet/GetLimiteGoods</welcome-file> <welcome-file>servlet/GetLimiteGoods</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.htm</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list> <filter> <display-name>CharFilter</display-name> <filter-name>CharFilter</filter-name> <filter-class>Filter.CharFilter</filter-class> </filter> <filter-mapping> <filter-name>CharFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>