前台界面项目根路径获取和使用
HTML中获取项目根路径的方法background-image: url(${request.contextPath}/before/images/image_3.jpg);
JSP中获取项目根路径的方法background-image: url(${pageContext.request.contextPath}/before/images/image_3.jpg)
<link rel="stylesheet" href="${request.contextPath}/before/css/showBo.css">
<script src="${request.contextPath}/before/js/jquery-3.2.1.min.js"></script>