实现多个JSP页面共用一个菜单

1.首先将菜单栏代码独立为一个jsp页面

例如

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<nav class="navbar navbar-inverse navbar-fixed-top">
	<div class="container">
		<div class="navbar-header">
			<button type="button" class="navbar-toggle collapsed"
				data-toggle="collapse" data-target="#navbar" aria-expanded="false"
				aria-controls="navbar">
				<span class="sr-only">Toggle navigation</span> <span
					class="icon-bar"></span> <span class="icon-bar"></span> <span
					class="icon-bar"></span>
			</button>
			<a class="navbar-brand" href="#">商城系统</a>
		</div>
		<div id="navbar" class="collapse navbar-collapse">
			<ul class="nav navbar-nav">
			<li class="dropdown"><a href="showgoods.do" >商城首页</a></li>
				<li class="dropdown"><a href="#" class="dropdown-toggle"
					data-toggle="dropdown" role="button" aria-haspopup="true"
					aria-expanded="false">分类 <span class="caret"></span></a>
					<ul class="dropdown-menu">
						<li><a href="categoryList.do">所有分类</a></li>
						<li><a href="category/add.jsp">添加分类</a></li>
					</ul></li>
				<li class="dropdown"><a href="#" class="dropdown-toggle"
					data-toggle="dropdown" role="button" aria-haspopup="true"
					aria-expanded="false">商品 <span class="caret"></span></a>
					<ul class="dropdown-menu">
						<li><a href="addgoods.jsp">添加商品</a></li>
						<li><a href="querygoods.do">所有商品</a></li>
					</ul></li>
			</ul>

			<ul class="nav navbar-nav navbar-right">
				<li class="dropdown"><a href="#" class="dropdown-toggle"
					data-toggle="dropdown" role="button" aria-haspopup="true"
					aria-expanded="false">${sessionScope.user.username} <span
						class="caret"></span></a>
					<ul class="dropdown-menu">
						<li><a href="logout.do">退出</a></li>
					</ul></li>
			</ul>
		</div>
	</div>
</nav>

2.用jsp内部标签引入菜单栏

<jsp:include page="文件名.jsp" />