jsp页面如何对map集合遍历

Map<Class,List<Student>>mapSet=newHashMap<Class,List<Student>>();map集合中，key的值是班级class... Map<Class,List<Student>> mapSet= new HashMap<Class,List<Student>>();
map集合中，key的值是班级class, value是每个班级对应的学生集合，现在想在页面显示不知道如何遍历map
页面效果应如下：（和贴吧差不多）
班级一：
学生A
学生B
学生C
班级二：
学生A1
学生B1
学生C1

先在我这样写,但是不对，items="${item.key}"中key取不到值
<c:forEach items="${mapSet}" var="item">
<c:forEach items="${item.key}" var="var">
${var.name}

</c:forEach>
<c:forEach items="${item.value}" var="s">
${s.name}

</c:forEach>
</c:forEach>

请大神给修改一下jsp页面写法展开

 我来答

2个回答

#合辑# 面试问优缺点怎么回答最加分？

百度网友96ffcf7
推荐于2016-09-25 · 知道合伙人互联网行家

百度网友96ffcf7
知道合伙人互联网行家

采纳数：22721 获赞数：118724

从事多年网络方面工作，有丰富的互联网经验。

向TA提问私信TA

关注

展开全部

MapAction.java

Java代码
package com.zx.demo.action;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.opensymphony.xwork2.ActionSupport;
import com.zx.demo.model.Product;
import com.zx.demo.model.Student;

public class MapAction extends ActionSupport
{

private Map<String,String> map;

private Map<String,Student> studentMap;

private Map<String,String[]> arrayMap;

private Map<String,List<Student>> listMap;

public String testMap()
{
map=new HashMap<String,String>();
map.put("1", "one");
map.put("2", "two");

studentMap=new HashMap<String,Student>();
studentMap.put("student1",new Student(new Long(1),"20034140201","张三1","男",25));
studentMap.put("student2",new Student(new Long(2),"20034140202","张三2","女",26));
studentMap.put("student3",new Student(new Long(3),"20034140202","张三3","男",27));

arrayMap=new HashMap<String,String[]>();
arrayMap.put("arr1", new String[]{"1","2003401","leejie","male","20"});
arrayMap.put("arr2", new String[]{"2","2003402","huanglie","male","25"});
arrayMap.put("arr3", new String[]{"3","2003403","lixiaoning","male","21"});

listMap=new HashMap<String,List<Student>>();

List<Student> list1=new ArrayList<Student>();
list1.add(new Student(new Long(1),"20034140201","张三1","男",25));
list1.add(new Student(new Long(2),"20034140202","张三2","男",25));
list1.add(new Student(new Long(3),"20034140203","张三3","男",25));
listMap.put("class1", list1);

List<Student> list2=new ArrayList<Student>();
list2.add(new Student(new Long(1),"20034140301","李四1","男",20));
list2.add(new Student(new Long(2),"20034140302","李四2","男",21));
list2.add(new Student(new Long(3),"20034140303","李四3","男",22));
list2.add(new Student(new Long(4),"20034140304","李四4","男",23));
listMap.put("class2", list2);

return SUCCESS;

}

public Map<String, String> getMap() {
return map;
}

public void setMap(Map<String, String> map) {
this.map = map;
}

public Map<String, Student> getStudentMap() {
return studentMap;
}

public void setStudentMap(Map<String, Student> studentMap) {
this.studentMap = studentMap;
}

public Map<String, String[]> getArrayMap() {
return arrayMap;
}

public void setArrayMap(Map<String, String[]> arrayMap) {
this.arrayMap = arrayMap;
}

public Map<String, List<Student>> getListMap() {
return listMap;
}

public void setListMap(Map<String, List<Student>> listMap) {
this.listMap = listMap;
}

}

2.testMap.jsp

Java代码
<%@ page contentType="text/html;charset=UTF-8" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>struts2中的map遍历总结</title>
</head>
<body>
<b>1.map中的value为String字符串</b><br>
<s:iterator value="map" id="column">
<s:property value="#column"/><br>
key: <s:property value="key"/><br>
value:<s:property value="value"/><br>
******************************************<br>
</s:iterator>

<b>2.map中的value为Student对象</b>
<table border="1" width="50%" cellspacing="0" cellpadding="0">
<tr>
<td>key=value</td>
<td>ID</td>
<td>num</td>
<td>name</td>
<td>sex</td>
<td>age</td>
</tr>
<s:iterator value="studentMap" id="column">
<tr>
<td><s:property value="#column"/></td>
<td><s:property value="value.id"/></td>
<td><s:property value="value.num"/></td>
<td><s:property value="value.name"/></td>
<td><s:property value="value.sex"/></td>
<td><s:property value="value.age"/></td>
</tr>
</s:iterator>
</table>
<p>

<b>3.map中的value为String数组</b>
<table border="1" width="50%" cellspacing="0" cellpadding="0">
<tr>
<td>key=value</td>
<td>ID</td>
<td>num</td>
<td>name</td>
<td>sex</td>
<td>age</td>
</tr>
<s:iterator value="arrayMap" id="column">
<tr>
<td><s:property value="#column"/></td>
<td><s:property value="value[0]"/></td>
<td><s:property value="value[1]"/></td>
<td><s:property value="value[2]"/></td>
<td><s:property value="value[3]"/></td>
<td><s:property value="value[4]"/></td>
</tr>
</s:iterator>
</table>
<p>
<b>4.map中的value为list集合</b>
<table border="1" width="50%" cellspacing="0" cellpadding="0">
<tr>
<td>class</td>
<td>ID</td>
<td>num</td>
<td>name</td>
<td>sex</td>
<td>age</td>
</tr>

<s:iterator value="listMap" id="column">
<s:set name="total" value="#column.value.size"/>
<s:iterator value="#column.value" status="s">
<tr>
<s:if test="#s.first"><td rowspan="${total}"><s:property value="#column.key"/></td></s:if>
<td><s:property value="id"/></td>
<td><s:property value="num"/></td>
<td><s:property value="name"/></td>
<td><s:property value="sex"/></td>
<td><s:property value="age"/></td>
</tr>
</s:iterator>
</s:iterator>
</table>

</body>
</html>

已赞过 已踩过<

评论收起

nefu_20061617
推荐于2016-10-06 · TA获得超过2342个赞

知道大有可为答主

回答量：1064

采纳率：72%

帮助的人：1480万

我也去答题访问个人页

关注

展开全部

${item.key}中的key的值是你定义的一个班级Class对象，它不是可遍历的对象。
应该把
<c:forEach items="${item.key}" var="var">
${var.name}
</c:forEach>
改为
${item.key.name}

追问

问题已经解决，你说的也对

本回答被提问者和网友采纳

已赞过 已踩过<

评论收起

推荐律师服务：若未解决您的问题，请您详细描述您的问题，通过百度律临进行免费专业咨询

jsp页面如何对map集合遍历

其他类似问题

为你推荐：