这个JSP页面的62行根本没实例化对象，连声明都没写，为什么还可以执行方法？

Question

<%@page import="java.text.SimpleDateFormat"%>
<%@page import="cn.pb.news.entity.News"%>
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@include file="../../common/common.jsp" %>
<script type="text/javascript">

	var flag = '${param.flag}';
	if(flag != null && flag != '' && flag != undefined) {
		if(flag == 'success') {
			alert('删除成功');
		}else if(flag == 'failed') {
			alert('删除失败');
		}
	}
	
	function addNews() {
		window.location = "newsDetailCreateSimple.jsp";
	}
</script>
  <div class="main-content-right">
        <!--即时新闻-->
        <div class="main-text-box">
            <div class="main-text-box-tbg">
                <div class="main-text-box-bbg">
                    <form name ="searchForm" id="searchForm" action="/news/jsp/admin/newsDetailList.jsp" method="post">
		 	<div>
		 				新闻分类：
		 					<select name="categoryId">
		 						<option value="0">全部</option>
			        			
			        				<option value='1' >国内</option>
			        			
			        				<option value='2' >国际</option>
			        			
			        				<option value='3' >娱乐</option>
			        			
			        				<option value='4' >军事</option>
			        			
			        				<option value='5' >财经</option>
			        			
			        				<option value='6' >天气</option>
			        			
	        				</select>
		 				新闻标题<input type="text" name="title" id="title" value=''/>
		 					<button type="submit" class="page-btn">GO</button>
		 					<button type="button" onclick="addNews();" class="page-btn">增加</button>
		 					<input type="hidden" name="currentPageNo" value="1"/>
		 					<input type="hidden" name="pageSize" value="10"/>
		 					<input type="hidden" name="totalPageCount" value="2"/>
		 	</div>
		 	</form>
			<table cellpadding="1" cellspacing="1" class="admin-list">
				<thead >
					<tr class="admin-list-head">
						<th>新闻标题</th>
                        <th>作者</th>
                        <th>时间</th>
                        <th>操作</th>
                    </tr>
                </thead>
                <%
                	List<News> newsList=newsService.getNewsList();
                	int i=0;
                	for(News news:newsList){
                		i++;
                %>
                <tbody>
                	<tr <%if(i % 2 != 0){%>class="admin-list-td-h2"<%} %>>
                		<td><a href='adminNewsView.jsp?id=2'><%=news.getTitle() %></a></td>
                		<td><%=news.getAuthor()%></td>
                		<td><%=new SimpleDateFormat("yyyy-MM-dd").format(news.getCreateDate())  %></td>
                		<td>
                			<a href='adminNewsCreate.jsp?id=2'>修改</a>
                			<a href="javascript:if(confirm('确认是否删除此新闻？')) location='adminNewsDel.jsp?id=2'">删除</a>
                		</td>
                	</tr> 
                </tbody>
                <%
                	}
                %>
            </table>
           <div class="page-bar">
			<ul class="page-num-ul clearfix">
				<li>共7条记录&nbsp;&nbsp; 1/2页</li>
				<a href="javascript:page_nav(document.forms[0],2);">下一页</a>
				<a href="javascript:page_nav(document.forms[0],2);">最后一页</a>&nbsp;&nbsp;
			</ul>
		 <span class="page-go-form"><label>跳转至</label>
	     <input type="text" name="inputPage" id="inputPage" class="page-key" />页
	     <button type="button" class="page-btn" onClick='jump_to(document.forms[0],document.getElementById("inputPage").value)'>GO</button>
		</span>
		</div> 
        </div>
       </div>
   </div>
   </div>
</div>

Answer 1

这是jsp+servlet，加载页面时通过反射配置在web.xml下的servlet就会自动执行对应servlet下的方法