我需要实现简单的分页，每页显示100条记录，分页数据按日期排序。虽然我已经正确排序了信息，但是我无法考虑分页逻辑，因为结果集在地图内部，再次将地图保持在里面它，
下面是我的JSTL代码以及我在其中添加结果集数据后迭代的TitleList / Title的定义。
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="${Title.value}"/></a></p>
</c:forEach>
</c:forEach>
虽然我可以通过将结果集直接添加到列表来对其进行分页，但是这会通过排序我正在寻找的顺序和功能来解决。对于上面的代码，我需要限制每页100条记录然后实现Next按钮再次显示100条记录。 对此表示赞赏。
更新：添加更多信息，这就是我在创建titlelist和titlemap的servlet中的地图，
map = {2012-07-12={160=tstng, 159=testing}, 2012-07-10={158=test, 157=test, 156=Testing, 155=Testing, 154=Testing, 153=Testing, 152=Testing, 151=Testing, 150=Testing, 149=Testing, 148=Testing, 147=Testing, 146=Testing, 145=Testing, 144=Testing, 143=Testing, 142=Testing, 141=Teasting, 140=Teasting, 139=Testing, 138=Testing, 137=Testing , 136=Testing for testing, 135=Testing for testing, 134=Testing for Test, 133=Testing}, 2012-07-04={132=Testing for Broker}, 2012-07-03={131=Testing for Post, 130=1200 TESTIN}, 2012-07-01={129=testing}, 2012-03-30={128=upload test}, 2012-03-28={127=test}, 2012-01-08={126=1BHK flat for 1000$ 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I，它将在从DB读取后创建地图
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"));
}
}
这是我尝试过的Richz， 这是我在dao课程中得到的内容，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);
}
和jsp
<c:foreach var="Titlelist" items="${Titlelist}">
EL for title,id and title
</c:foreach>
With this approach I can do pagination date wise along pages and data looks like below along with pagination
Date10 title10
Date10 title09
However I need data in this format,
Date 10
title10
title09
我尝试了列表清单，但由于某些原因我无法做到。我正在失去列之间的关系。我的网络搜索显示我上面列出的分页。
8月31日更新了详细信息，
Ok Richz这里是我的JSP，我使用了与你完全相同的结构。
<%@page import="java.util.LinkedHashMap"%>
<%@page import="java.util.Date"%>
<%@page import="java.util.Map"%>
<%@page import="java.util.List"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@ include file="/header.jsp" %>
<%@ include file="WEB-INF/jspf/navdisplay.jspf" %>
<%@page import="java.util.ArrayList"%>
<%@page session="true" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<!DOCTYPE html>
<html>
<head>
<title>DB Test</title>
</head>
<body>
<c:set var="dateTotal" scope="session" value="${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，
List list = 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，
总行数是：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 =品尝， 140 = Teasting，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Broker}，2012-07-03 = {131 =测试发布，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持续1000美元在Journal Square}，2012-01-04 = {125 = tseting by kiran，124 = tseting by kiran，123 = tseting by kiran，122 = kiran，121 = kiran，120 = kiran，119 = kiran，118 = kiran，117 = kiran，116 = kiran，115 = titing by kiran ，114 = kiran，113 = kiran，112 = kiran，111 = kiran，110 = tseting by kiran，110 = kiran，109 = kiran，108 = kiran，107 = kiran，106 = kiran，105 = kiran tseting，104 = kiran tseting}，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 =测试，77 =测试，76 =测试，75 =测试，74 =测试}，2011-12-09 = {73 =每月消费者价格指数较去年同期上涨4.2％，反映出10月份的大幅放松增加了5.5％。 }，2011-12-08 = {72 =测试dispplay}，2011-11-25 = {71 = Journal Square的公寓出租，价格为1000美元。请看现在。，70 =公寓出租1000美元。请发布。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 = tEST，59 = TESTING，58 = TESTING，57 =测试，56 =测试，55 =测试，54 = tseting，53 =测试，52 =测试，51 =测试，50 = teting，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 = TETING，37 =测试}，2011-11-22 = {36 =测试，35 =测试，34 =测试，33 = Kiran测试，32 =测试，31 =测试，30 = Kiran测试，29 =测试by 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 =测试，20 =测试， 19 =测试，18 = ESTING，17 = ESTING，16 = ESTING，15 = ESTING，14 = kiran测试，13 = Kiran测试，12 = Kiran测试，11 = Kiran测试，10 = Testin g by Kian，9 = Kiran测试，8 = Kiran测试，7 = Kran测试，6 =测试，5 = Kiran测试，4 = Kiran测试}，2011-11-20 = {3 =测试，2 =测试，1 =测试}}]
答案 0 :(得分：0)
在这种情况下，我假设您正在从数据库中检索所有记录，现在您要对其进行排序并在页面上一次只显示100条记录。要解决此问题，您可以遵循方法
如果您有一个很大的列表，那么以这种方式进行分页可能会影响性能，因为这个列表需要存储在会话中以便来自同一用户的后续请求。
答案 1 :(得分：0)
请尝试此演示页。
<%@ page import="java.util.*" %>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
<%
//dummy data
List<Map> list = new ArrayList<Map>();
long now = new Date().getTime();
for(int i = 1; i < 4; i++){
LinkedHashMap<Integer, String> titleMap = new LinkedHashMap<Integer, String>();
for(int j = 1; j < 43 ;j++){
titleMap.put(j, "title" + j);
}
Map<Date, LinkedHashMap<Integer, String>> dateMap = new LinkedHashMap<Date, LinkedHashMap<Integer, String>>();
dateMap.put(new Date(now + 1000*60*60*25* i), titleMap);
list.add(dateMap);
}
pageContext.setAttribute("list", list);
%>
<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>