import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;
public class MapTest4 {
public static void main(String[] args) {
Map<String, String> map1=new HashMap<String, String>();
map1.put("aqw", "安全网");
map1.put("ceshi", "测试网");
map1.put("ali", "阿里网");
map1.put("ali", "阿里1网");
//jdk1.4中
//遍历方法一
/* Set<Entry<String, String>> se1= map1.entrySet();
Iterator it=se1.iterator();
while(it.hasNext()){
Entry en1=(Entry)it.next();
Object key=en1.getKey();
Object value=en1.getValue();
System.out.println("输出key："+key+" "+"输出value:"+value);
}*/
//通过先获取到所有的key然后通过key遍历出所有的value
//遍历方法二
/*Set<String> set=map1.keySet(); //得到所有key的集合
for(String str:set){
String str1=map1.get(str);
System.out.println(str+" "+str1);
}*/
//通过map.entryset()遍历key和value,---推荐，尤其容量大时---
//JDE1.5中，应用新特性For循环遍历
//遍历方法三
for(Entry<String, String> en1:map1.entrySet()){
System.out.println(en1.getKey());
System.out.println(en1.getValue());
}
//返回所有的值，但是不能得到key,如果key相同，只会取一个，按照顺序取最后一个value
//遍历方法4
/*for(String v:map1.values()){
System.out.println(v);
}*/
}
}
//jsp页面放入select下拉中一种写法
<%
Map<String, String> goods = 获取到的Map集合;
for (Map.Entry<String, String> en : goods.entrySet()) {
out.print("<option value=\""
+ en.getKey()
+ "\""
+ (dgood.indexOf(en.getKey()) != -1 ? " selected=\"selected\""
: "") + ">" + en.getValue() + "</option>");
}
%>实例：
1.jsp页面
<%@ page language="java" import="java.util.Map" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
Map<String,String> menus=(Map<String,String>)request.getAttribute("menus");
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
<script type="text/javascript" src="http://apps.bdimg.com/libs/jquery/1.6.4/jquery.min.js"></script>
</head>
<body>
<input type="text" name="name" value="${name }"/>
<select>
<!-- 这种indexOf方式不好,多的时候容易出问题啦！如果key是拼音简写这些 -->
<%-- <%
Map<String, String> goods = menus;
String dgood="al";
for (Map.Entry<String, String> en : goods.entrySet()) {
out.print("<option value=\""
+ en.getKey()
+ "\""
+ (dgood.indexOf(en.getKey()) != -1 ? " selected=\"selected\""
: "") + ">" + en.getValue() + "</option>");
}
%> --%>
<!--这儿简单的egood.equals(en.getkey())如果替换成用en.getkey().equals(egood)时候量很大还是其它原因是会报错的！所以就这样写 -->
<%
Map<String, String> egoods = menus;
String egood="aly";
for (Map.Entry<String, String> en : egoods.entrySet()) {
out.print("<option value=\""
+ en.getKey()
+ "\""
+ (egood.equals(en.getKey()) ? " selected=\"selected\""
: "") + ">" + en.getValue() + "</option>");
}
%>
</select>
</body>
</html>
2.controller控制器
package com.bbaqw.controller;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
@Controller
public class FourController {
@RequestMapping("show")
public ModelAndView showInfo(HttpServletRequest reqeust,HttpServletResponse response){
ModelAndView mav=new ModelAndView("/index");
mav.addObject("name", "夏利");
Map<String,String> map=new HashMap<String,String>();
map.put("aly", "阿里云");
map.put("al", "阿里");
map.put("bd", "百度");
map.put("albb", "阿里吧吧");
map.put("bbal", "吧吧阿里");
map.put("tx", "腾讯");
map.put("txhd", "腾讯互动");
mav.addObject("menus", map);
return mav;
}
}
