package app05b;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* 城市控制类
*/
@WebServlet( name = "BigCitiesServlet", urlPatterns = "/bigCities")
public class BigCitiesServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public BigCitiesServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
*
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 创建map集合
Map<String, String> capitals = new HashMap<String, String>();
// 放入键值对
capitals.put("Indonesia", "Jakarta");
capitals.put("Malaysia", "Kuala Lumpur");
capitals.put("Thailand", "Bangkok");
// 向页面传递参数
request.setAttribute("capitals", capitals);
// 创建map集合,值是数组
Map<String, String[]> bigCities = new HashMap<String,String[]>();
// 放入值
bigCities.put("Australia", new String[] {"Sydney",
"Melbourne", "Perth"});
bigCities.put("New Zealand", new String[] {"Auckland",
"Christchurch", "Wellington"});
bigCities.put("Indonesia", new String[] {"Jakarta",
"Surabaya", "Medan"});
request.setAttribute("capitals", capitals);
request.setAttribute("bigCities", bigCities);
/*Set s = bigCities.keySet();
Iterator it = s.iterator();
while(it.hasNext()){
System.out.println(it.next());
}*/
// 重定向
RequestDispatcher rd = request.getRequestDispatcher("/Cities.jsp");
rd.forward(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
jsp页面(需要引入jstl的两个jar包)
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!-- 引入jstl标签库 -->
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix = "c" %>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Big Cities</title>
<style>
table,tr,td{
border: 1px solid #ae7;
padding: 3px;
}
</style>
</head>
<body>
Capitals
<table>
<tr style="background:#448755;color:white;font-weight:bold;">
<td>Country</td>
<td>Capital</td>
</tr>
<!-- 遍历map集合 -->
<c:forEach items="${ requestScope.capitals}" var="mapItem">
<tr>
<td>${mapItem.key }</td>
<td>${mapItem.value }</td>
</tr>
</c:forEach>
</table>
<br>
Big Cities
<table>
<tr style="background:#448755;color:white;font-weight:bold;">
<td>Country</td>
<td>Cities</td>
</tr>
<!-- foreach遍历 -->
<c:forEach items="${ requestScope.bigCities }" var= "mapItem">
<tr>
<td>${mapItem.key }</td>
<td>
<!-- 由于值是String数组,因此需要进一步遍历 -->
<c:forEach items="${mapItem.value }" var="city" varStatus="status">
${city}<c:if test="${!status.last }">,</c:if>
</c:forEach>
</td>
</tr>
</c:forEach>
</table>
</body>
</html>