【JSTL】--JSTL表达式：c:forEach，varstatus/begin end/循环控制标签--drp215
jstl_core.jsp
<%@ page language="java" contentType="text/html; charset=GB18030"
pageEncoding="GB18030"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ page import="com.bjpowrnode.jstl.*" %>
<%@ page import="java.util.*" %>
<!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=GB18030">
<title>Insert title here</title>
</head>
<body>
<h3>采用forEach标签，varstatus</h3><br>
<table border="1">
<tr>
<td>用户名称</td>
<td>年龄</td>
<td>所属组</td>
</tr>
<c:choose>
<c:when test="${empty users}">
<tr>
<td colspan="3">没有符合条件的数据</td>
</tr>
</c:when>
<c:otherwise>
<c:forEach items="${users }" var="user" varStatus="vs">
<c:choose>
<c:when test="${vs.count mod 2==0 }">
<tr bgcolor="red">
</c:when>
<c:otherwise>
<tr>
</c:otherwise>
</c:choose>
<td>${user.username}</td>
<td>${user.age }</td>
<td>${user.group.name }</td>
<tr>
</c:forEach>
</c:otherwise>
</c:choose>
</table>
<h3>采用forEach标签,begin ,end</h3>
<table border="1">
<tr>
<td>用户名称</td>
<td>年龄</td>
<td>所属组</td>
</tr>
<c:choose>
<c:when test="${empty users }">
<tr>
<td colspan="3" >没有符合条件的数据</td>
</tr>
</c:when>
<c:otherwise>
<c:forEach items="${users}" var="user" begin="2" end="8" step="2">
<tr>
<td>${user.username}</td>
<td>${user.age }</td>
<td>${user.group.name }</td>
</tr>
</c:forEach>
</c:otherwise>
</c:choose>
</table>
<li>演示循环控制标签：forEach,输出Map</li><br>
<c:forEach items="${map }" var ="entry">
${entry.key },${entry.value}<br>
</c:forEach>
<li>循环控制标签：forTokens</li><br>
<c:forTokens items= "${strTokens}" delims="#" var="v">
${v }<br>
</c:forTokens>
</body>
</html>
JstlCoreServlet
/**
*
*/
package com.bjpowrnode.jstl;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* @ClassName:JstlCoreServlet
* @Description:TODO
* @author wm
* @date 2016年2月15日上午11:40:32
*/
public class JstlCoreServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//普通字符串
request.setAttribute("hello","Hello World!");
request.setAttribute("welcome", "<font color='red'>欢迎你来到这个世界！</font>");
//条件控制标签、
request.setAttribute("v1", 10);
request.setAttribute("v2", 20);
request.setAttribute("userList", new ArrayList());
//结构
Group group =new Group();
group.setName("动力节点drp 603班");
List users=new ArrayList();
for(int i =0;i<10;i++){
User user=new User();
user.setUsername("张三_"+i );
user.setAge(23+i);
user.setGroup( group);
users.add(user);
}
request.setAttribute("users", users);
//map
Map map=new HashMap();
map.put("k1", "v1");
map.put("k2", "v2");
map.put("k3", "v3");
map.put("k4", "v4");
request.setAttribute("map", map);
//forTokens
request.setAttribute("strTokens", "1#2#3#4#5");
request.getRequestDispatcher("/jstl_core.jsp").forward(request, response);
}
}
