JSP JSTL函数<fn>

本文介绍了JSTL(JSP Standard Tag Library)中用于字符串处理的函数,通过具体示例展示了如何使用fn:substring和fn:length函数来截取字符串及获取集合长度。

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参考 http://www.runoob.com/jsp/jsp-jstl.html

JSTL包含一系列标准函数,大部分是通用的字符串处理函数。

两个JSTL函数 嵌套使用。

@RequestMapping("/view")
public String view(Model model) {

    model.addAttribute("name", "这是一个人的名字");

    return "watchPoint/view";
}
<div>
    截取掉第一个和最后一个字符${fn:substring(name, 1, fn:length(name)-1)}
</div>

在view页面获取EL表达式的长度:fn:length()函数返回字符串长度或集合中元素的数量

import org.springframework.ui.Model;

@RequestMapping("/view")
@RequiresPermissions("emergencyNotice:view")
public String viewEmergencyNotice( Model model) {

    /* 查询所有该通知的读取记录(所有用户) */
    List<EmergencyNoticeRead> eNoticeReads = new ArrayList<EmergencyNoticeRead>();
    model.addAttribute("eNoticeReads", eNoticeReads);// 把所有的读取记录传到前台

    return "emergencyNotice/view";
}
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>

<div>
    长度:<span>${fn:length(eNoticeReads)}</span>
</div>

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %> <html> <head> <!-- 页面meta --> <meta charset="utf-8"> <title>书虫补给站</title> <link rel="stylesheet" href="${pageContext.request.contextPath}/css/bootstrap.css"> <link rel="stylesheet" href="${pageContext.request.contextPath}/css/AdminLTE.css"> <link rel="stylesheet" href="${pageContext.request.contextPath}/css/_all-skins.min.css"> <script src="${pageContext.request.contextPath}/js/jquery.min.js"></script> <script src="${pageContext.request.contextPath}/js/bootstrap.js"></script> <script src="${pageContext.request.contextPath}/js/app.js"></script> <script type="text/javascript"> function SetIFrameHeight() { var iframeid = document.getElementById("iframe"); //iframe id if (document.getElementById) { iframeid.height = document.documentElement.clientHeight; } } </script> </head> <body class="hold-transition skin-purple sidebar-mini"> <div class="wrapper"> <!-- 页面头部 --> <header class="main-header"> <!-- Logo --> <a href="${pageContext.request.contextPath}/admin/index.jsp" class="logo"> <!-- mini logo for sidebar mini 50x50 pixels --> <span class="logo-mini"><b>智阅云联</b></span> <!-- logo for regular state and mobile devices --> <span class="logo-lg"><b>书虫补给站</b></span> </a> <!-- Header Navbar: style can be found in header.less --> <nav class="navbar navbar-static-top"> <nav class="navbar navbar-static-top"> <div class="navbar-custom-menu"> <ul class="nav navbar-nav"> <li class="dropdown user user-menu"> <a > <img src="${pageContext.request.contextPath}/img/user1.jpg" class="user-image" alt="User Image"> <span class="hidden-xs">${USER_SESSION.name}</span> </a> </li> <li class="dropdown user user-menu"> <a href="${pageContext.request.contextPath}/userServlet?method=logout"> <span class="hidden-xs">注销用户</span> </a> </li> </ul> </div> </nav> </nav> </header> <!-- 页面头部 /--> <!-- 导航侧栏 --> <aside class="main-sidebar"> <!-- sidebar: style can be found in sidebar.less --> <section class="sidebar"> <!-- /.search form --> <!-- sidebar menu: : style can be found in sidebar.less --> <ul class="sidebar-menu"> <li id="admin-index"> <a href="${pageContext.request.contextPath}/admin/index.jsp"> <i class="fa fa-dashboard"></i> <span><b>新书推荐</b></span> </a> </li> <li> <a href="${pageContext.request.contextPath}/bookServlet?method=search" target="iframe"> <i class="fa fa-circle-o"></i> <span><b>图书借阅</b></span> </a> </li> <li> <a href="${pageContext.request.contextPath}/bookServlet?method=searchBorrowed" target="iframe"> <i class="fa fa-circle-o"></i> <span><b>当前借阅</b></span> </a> </li> <li> <a href="${pageContext.request.contextPath}/recordServlet?method=searchRecords" target="iframe"> <i class="fa fa-circle-o"></i> <span><b>借阅记录</b></span> </a> </li> </ul> </section> <!-- /.sidebar --> </aside> <!-- 导航侧栏 /--> <!-- 内容区域 --> <div class="content-wrapper"> <iframe width="100%" id="iframe" name="iframe" onload="SetIFrameHeight()" frameborder="0" src="${pageContext.request.contextPath}/bookServlet?method=selectNewbooks"></iframe> </div> </div> </body> </html>帮我优化一下这段代码
06-19
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