【发布时间】：2012-08-06 06:28:52
【问题描述】：
我需要实现简单的分页，每页显示 100 条记录，并且分页数据按日期排序。虽然我已经对信息进行了正确排序，但是我无法考虑分页逻辑，因为结果集在地图内部，地图又在里面它，
下面是我的 JSTL 代码以及 TitleList/Title 的定义，我在其中添加结果集数据后正在对其进行迭代。
Map<Date, LinkedHashMap<Integer, String>> TitleList = new LinkedHashMap<Date, LinkedHashMap<Integer, String>>();
LinkedHashMap<Integer, String> Title = new LinkedHashMap<Integer, String>();
<c:forEach items="${TitleList}" var="column">
<p><c:out value="${column.key}"/></p>
<c:forEach var="Title" items="${column.value}">
<p><a href="<%=request.getContextPath()%>/Test.do?id=${Title.key}"><c:out value="${Title.value}"/></a></p>
</c:forEach>
</c:forEach>
虽然我可以通过将结果集直接添加到列表来对其进行分页，但是这会被我正在寻找的排序顺序和功能杀死。不知何故，对于上面的代码，我需要限制每页 100 条记录，然后实现下一步按钮，这将再次显示 100 条记录。 感谢您对此的一些想法。
更新：添加更多信息，这是地图在我创建标题列表和标题地图的 servlet 中的样子，
map = {2012-07-12={160=tstng, 159=testing}, 2012-07-10={158=test, 157=test, 156=Testing, 155=Testing, 154=Testing, 153=Testing, 152=Testing, 151=Testing, 150=Testing, 149=Testing, 148=Testing, 147=Testing, 146=Testing, 145=Testing, 144=Testing, 143=Testing, 142=Testing, 141=Teasting, 140=Teasting, 139=Testing, 138=Testing, 137=Testing , 136=Testing for testing, 135=Testing for testing, 134=Testing for Test, 133=Testing}, 2012-07-04={132=Testing for Broker}, 2012-07-03={131=Testing for Post, 130=1200 TESTIN}, 2012-07-01={129=testing}, 2012-03-30={128=upload test}, 2012-03-28={127=test}, 2012-01-08={126=1BHK flat for 1000$ at Journal Square}, 2012-01-04={125=tseting by kiran, 124=tseting by kiran, 123=tseting by kiran, 122=tseting by kiran, 121=tseting by kiran, 120=tseting by kiran, 119=tseting by kiran, 118=tseting by kiran, 117=tseting by kiran, 116=tseting by kiran, 115=tseting by kiran, 114=tseting by kiran, 113=tseting by kiran, 112=tseting by kiran, 111=tseting by kiran, 110=tseting by kiran, 109=tseting by kiran, 108=tseting by kiran, 107=tseting by kiran, 106=tseting by kiran, 105=tseting by kiran, 104=tseting by kiran}, 2012-01-02={103=testing, 102=testing, 101=testing, 100=testing, 99=testing, 98=testing, 97=testing, 96=testing, 95=testing, 94=testing, 93=testing, 92=testing, 91=testing, 90=testing, 89=testing, 88=testing, 87=testing, 86=testing, 85=testing, 84=testing, 83=testing, 82=testing, 81=testing, 80=testing, 79=testing, 78=testing, 77=testing, 76=testing, 75=testing, 74=testing}, 2011-12-09={73=The monthly consumer price index rose 4.2% from the year-ago period, reflecting a huge easing from Octoberâ??s 5.5% increase. }, 2011-12-08={72=Testing for dispplay}, 2011-11-25={71=Apartment for Rent at Journal Square for 1000$.Please see now., 70=Apartment for Rent at Journal Square for 1000$.Please see now., 69=testing, 68=AS, 67=A, 66=A, 65=q, 64=q, 63=Testing, 62=Testing}, 2011-11-24={61=testing, 60=tEST, 59=TESTING, 58=TESTING, 57=Testing, 56=Testing, 55=Testing, 54=tseting, 53=testing, 52=testing, 51=testing, 50=teting, 49=tESTING, 48=tESTING, 47=tESTING, 46=Testing, 45=TESTING, 44=TESTING, 43=tESTING}, 2011-11-23={42=Testing, 41=testing, 40=Testing, 39=tESTING, 38=TETING, 37=testing}, 2011-11-22={36=Testing, 35=Testing, 34=Testing, 33=Testing by Kiran, 32=testing, 31=Testing, 30=Testing by Kiran, 29=Testing byt kiran, 28=Testing by Kiran, 27=testing by kiran, 26=testing by kiran, 25=Testing , 24=TSETING, 23=Testing by Kiran}, 2011-11-21={22=testing, 21=Testng, 20=TESTING, 19=TESTING, 18=ESTING, 17=ESTING, 16=ESTING, 15=ESTING, 14=testing by kiran, 13=testing by Kiran, 12=Testing by Kiran, 11=testing by Kiran, 10=Testing by Kian, 9=Testing by Kiran, 8=Testing by Kiran, 7=Testing byKiran, 6=testing, 5=Test by Kiran, 4=Test by Kiran}, 2011-11-20={3=testing, 2=testing, 1=testing}}
下面是 servlet 代码，我将从 DB 读取后创建映射，
Map<Date, LinkedHashMap<Integer, String>> TitleList = new LinkedHashMap<Date, LinkedHashMap<Integer, String>>();
String sqld = "Select Distinct DATE(timestamp) as DATE from table ORDER BY DATE DESC LIMIT 730 ;";
ResultSet rsd = null;
try {
rsd = stmt1.executeQuery(sqld);
} catch (SQLException ex) {
Logger.getLogger(myclass.class.getName()).log(Level.SEVERE, null, ex);
}
try {
while (rsd.next()) {
LinkedHashMap<Integer, String> Title = new LinkedHashMap<Integer, String>();
// System.out.println("Testing");
Date Date = rsd.getDate("Date");
// System.out.println(Date);
String sql = "Select title,id from table Where DATE(timestamp) = '" + Date + "'ORDER BY id DESC";
// System.out.println(sql);
ResultSet rs = stmt.executeQuery(sql);
rs.last();
int numRows = rs.getRow();
// System.out.println(rs.getRow());
rs.beforeFirst();
while (rs.next()) {
for (int i = 1; i <= numRows; i++) {
String title = rs.getString("title");
Integer id = rs.getInt("id");
Title.put(id, title);
TitleList.put(Date, Title);
}
System.out.println("Size of LinkedHashMap for Title : " + Title.size());
// System.out.println(rs.getString("title"));
}
}
这是我尝试过 Richz 的东西， 这是我在 dao 课上得到的结果，我做了类似下面的事情，
string query ="select title,id,date(timestamp) as date from table";
list<TitleList> list = new ArrayList<Titlelist>();
try {
resultset rs = stmt.executeQuery(query);
while(rs.next()){
myclass myc = new myclass();
myc.setcid(rs.getInt("id");
myc.settitle(rs.getString("title");
myc.settimestamp(rs.gettimestamp("timestamp");
list.add(myc);
}
在jsp中
<c:foreach var="Titlelist" items="${Titlelist}">
EL for title,id and title
</c:foreach>
With this approach I can do pagination date wise along pages and data looks like below along with pagination
Date10 title10
Date10 title09
However I need data in this format,
Date 10
title10
title09
我尝试做列表列表，但由于某些原因我无法做到。我正在失去列之间的关系。我的互联网搜索显示我按上面对列表所做的分页。
8 月 31 日更新详情，
好的，Richz 这是我的 JSP，我使用的结构和你的完全一样。
<%@page import="java.util.LinkedHashMap"%>
<%@page import="java.util.Date"%>
<%@page import="java.util.Map"%>
<%@page import="java.util.List"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@ include file="/header.jsp" %>
<%@ include file="WEB-INF/jspf/navdisplay.jspf" %>
<%@page import="java.util.ArrayList"%>
<%@page session="true" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<!DOCTYPE html>
<html>
<head>
<title>DB Test</title>
</head>
<body>
<c:set var="dateTotal" scope="session" value="${fn:length(list)}"/>
<c:set var="currentDate" value="${param.date}"/>
<c:if test="${empty currentDate or currentDate < 0}">
<c:set var="currentDate" value="0"/>
</c:if>
<c:if test="${dateTotal <= currentDate}">
<c:set var="currentDate" value="${dateTotal - 1}"/>
</c:if>
<c:set var="perPage" scope="session" value="10"/>
<c:set var="pageStart" value="${param.start}"/>
<c:if test="${empty pageStart or pageStart < 0}">
<c:set var="pageStart" value="0"/>
</c:if>
<a href="?date=${currentDate - 1}">Previous Date</a> <a href="?date=${currentDate + 1}">Next Date</a><br/>
Titles <a href="?start=${pageStart - perPage}"><<</a>${pageStart + 1} - ${pageStart + perPage} <a href="?start=${pageStart + perPage}">>></a>
<c:forEach items="${list[currentDate]}" var="item" >
<p><c:out value="${item.key}"/></p>
<c:forEach var="Title" items="${item.value}" begin="${pageStart}" end="${pageStart + perPage - 1}" >
<p><a href="<%=request.getContextPath()%>/Test.do?id=${Title.key}"><c:out value="${Title.value}"/></a></p>
</c:forEach>
</c:forEach>
</body>
</html>
下面是为列表生成数据的servlet，
列表列表 = new ArrayList();
Map<Date, LinkedHashMap<Integer, String>> TitleList = new LinkedHashMap<Date, LinkedHashMap<Integer, String>>();
String sqld = "Select Distinct DATE(ctimestamp) as DATE from table ORDER BY DATE DESC LIMIT 730 ;";
ResultSet rsd = null;
try {
rsd = stmt1.executeQuery(sqld);
} catch (SQLException ex) {
Logger.getLogger(sortResultshs.class.getName()).log(Level.SEVERE, null, ex);
}
try {
while (rsd.next()) {
LinkedHashMap<Integer, String> Title = new LinkedHashMap<Integer, String>();
// System.out.println("Testing");
Date Date = rsd.getDate("Date");
// System.out.println(Date);
String sql = "Select title,id from table Where DATE(ctimestamp) = '" + Date + "'ORDER BY id DESC";
// System.out.println(sql);
ResultSet rs = stmt.executeQuery(sql);
rs.last();
int numRows = rs.getRow();
// System.out.println(rs.getRow());
rs.beforeFirst();
while (rs.next()) {
// List<String> Title = new ArrayList<String>();
for (int i = 1; i <= numRows; i++) {
String title = rs.getString("title");
Integer id = rs.getInt("id");
Title.put(id, title);
TitleList.put(Date, Title);
}
// System.out.println(rs.getString("title"));
}
list.add(TitleList);
}
列表如下所示，
总行数为：160 列表是：[{2012-07-12={160=tstng, 159=testing}, 2012-07-10={158=test, 157=test, 156=Testing, 155=Testing, 154=Testing, 153=测试, 152=测试, 151=测试, 150=测试, 149=测试, 148=测试, 147=测试, 146=测试, 145=测试, 144=测试, 143=测试, 142=测试, 141=测试, 140=测试, 139=测试, 138=测试, 137=测试, 136=测试测试, 135=测试测试, 134=测试测试, 133=测试}, 2012-07-04={132=测试测试Broker}, 2012-07-03={131=Posting 测试, 130=1200 TESTIN}, 2012-07-01={129=testing}, 2012-03-30={128=上传测试}, 2012-03 -28={127=test}, 2012-01-08={126=1BHK flat for 1000$ at Journal Square}, 2012-01-04={125=由 kiran 设置, 124=由 kiran 设置, 123=设置by kiran, 122=tseting by kiran, 121=tseting by kiran, 120=tseting by kiran, 119=tseting by kiran, 118=tseting by kiran, 117=tseting by kiran, 116=tseting by kiran, 115=tseting by kiran , 114=kiran 设置，113=kiran 设置，112=kiran 设置，111=kiran 设置，110 = 由 kiran 设置，109=由 kiran 设置，108=由 kiran 设置，107=由 kiran 设置，106=由 kiran 设置，105=由 kiran 设置，104=由 kiran 设置}，2012-01-02={103 =测试, 102=测试, 101=测试, 100=测试, 99=测试, 98=测试, 97=测试, 96=测试, 95=测试, 94=测试, 93=测试, 92=测试, 91=测试, 90=测试, 89=测试, 88=测试, 87=测试, 86=测试, 85=测试, 84=测试, 83=测试, 82=测试, 81=测试, 80=测试, 79=测试, 78 =testing, 77=testing, 76=testing, 75=testing, 74=testing}, 2011-12-09={73=月度消费者物价指数较去年同期上涨 4.2%，反映出从 10 月份开始大幅放缓â ??s 增加 5.5%。 }, 2011-12-08={72=测试显示}, 2011-11-25={71=Journal Square 1000 美元的公寓出租。请立即查看。, 70=1000 美元的公寓出租。请现在看。, 69=测试, 68=AS, 67=A, 66=A, 65=q, 64=q, 63=测试, 62=测试}, 2011-11-24={61=测试, 60=测试，59=测试，58=测试，57=测试，56=测试，55=测试，54=测试，53=测试，52=测试，51=测试，50=测试，49=测试，48=测试， 47=测试, 46=测试, 45=测试, 44=测试, 43=测试}, 2011-11-23={42=测试, 41=测试, 40=测试, 39=测试, 38=测试, 37= testing}, 2011-11-22={36=Testing, 35=Testing, 34=Testing, 33=Testing by Kiran, 32=Testing, 31=Testing, 30=Testing by Kiran, 29=Testing byt kiran, 28= Kiran 测试，27=kiran 测试，26=kiran 测试，25=测试，24=TSETING，23=Kiran 测试}，2011-11-21={22=测试，21=Testng，20=TESTING， 19=测试，18=测试，17=测试，16=测试，15=测试，14=kiran测试，13=Kiran测试，12=Kiran测试，11=Kiran测试，10=Testin g by Kian, 9=Testing by Kiran, 8=Testing by Kiran, 7=Testing by Kiran, 6=Testing, 5=Test by Kiran, 4=Test by Kiran}, 2011-11-20={3=testing, 2 =测试，1=测试}}]
【问题讨论】：
标签： servlets jdbc collections pagination jstl