我的 JSP 中有一个下拉菜单，我不想用文本对值进行硬编码，而是想从类中调用常量。这是我的常量类的片段，名为 master.dao.util.MasterDataConstants
//DIVISIONS FOR DROPDOWN
public static final String DIVISION_TYPE_DROPDOWN_AUDIT_MANAGEMENT_GLOBAL_ID = "Audit Management - Global";
public static final String DIVISION_TYPE_DROPDOWN_CHANGE_MANAGEMENT_GLOBAL_ID = "Change Management - Global";
public static final String DIVISION_TYPE_DROPDOWN_DEA_MANAGEMENT_GLOBAL_ID = "DEA Management - Global";
public static final String DIVISION_TYPE_DROPDOWN_EHS_MANAGEMENT_GLOBAL_ID = "EH&S Management - Global";
public static final String DIVISION_TYPE_DROPDOWN_EVENT_MANAGEMENT_GLOBAL_ID = "Event Management - Global";
这是我的 JSP 页面:
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page import="java.sql.*"%>
<%@ page import="java.io.*"%>
<%@ page import="java.util.*"%>
<%@ page import="javax.servlet.*"%>
<%@ page import="master.dao.MasterDataDao"%>
**<%@ page import="master.dao.util.MasterDataConstants"%>**
<%@ page import="master.dto.SiteDto"%>
<!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=ISO-8859-1">
<title>Master Data</title>
</head>
<script>
</script>
<body>
<form name="input" action="getMasterData" method="get">
<br />
<br />
<h1 align='center'>Master Data File</h1>
<br />
<br />
<table border="0" align='center'>
<tr>
<td>
<h2>Site Name</h2>
</td>
<td align='left'>
<jsp:useBean id="masterDao" clas s="master.dao.MasterDataDao"/>
<select name="siteId" id="siteId">
<option value="0">ALL</option>
<c:forEach items="${masterDao.allSites}" var="siteDto">
<option value="${siteDto.id}">${siteDto.name}</option>
</c:forEach>
</select></td>
</tr>
<tr>
<td>
**<h2>Division</h2>
</td>
<td align='left'>
<jsp:useBean id="masterDaoUtil" class="master.dao.util.MasterDataConstants"/>
<select name="divisionId" id="divisionId">
<option value="33">${MasterDataConstants.DIVISION_TYPE_DROPDOWN_AUDIT_MANAGEMENT_GLOBAL_ID} </option>
<option value="31">${MasterDataConstants.DIVISION_TYPE_DROPDOWN_CHANGE_MANAGEMENT_GLOBAL_ID} </option>
<option value="34">${MasterDataConstants.DIVISION_TYPE_DROPDOWN_DEA_MANAGEMENT_GLOBAL_ID}</option>
<option value="35">${MasterDataConstants.DIVISION_TYPE_DROPDOWN_EHS_MANAGEMENT_GLOBAL_ID}</option>
<option value="23">${MasterDataConstants.DIVISION_TYPE_DROPDOWN_EVENT_MANAGEMENT_GLOBAL_ID}</option>**
</select></td>
</tr>
</table>
<br />
<br />
<div style="text-align: center">
<input type="submit" value="Submit">
</div>
</form>
</body>
</html>
当我执行此页面时，我得到标记为“部门”的第二个下拉列表的空白值。我已经从 JSP 中复制了下面表示除法的部分:
<td>
<h2>Division</h2>
</td>
<td align='left'>
<jsp:useBean id="masterDaoUtil" class="master.dao.util.MasterDataConstants"/>
<select name="divisionId" id="divisionId">
<option value="33">${MasterDataConstants.DIVISION_TYPE_DROPDOWN_AUDIT_MANAGEMENT_GLOBAL_ID}</option>
<option value="31">${MasterDataConstants.DIVISION_TYPE_DROPDOWN_CHANGE_MANAGEMENT_GLOBAL_ID}</option>
<option value="34">${MasterDataConstants.DIVISION_TYPE_DROPDOWN_DEA_MANAGEMENT_GLOBAL_ID}</option>
<option value="35">${MasterDataConstants.DIVISION_TYPE_DROPDOWN_EHS_MANAGEMENT_GLOBAL_ID}</option>
<option value="23">${MasterDataConstants.DIVISION_TYPE_DROPDOWN_EVENT_MANAGEMENT_GLOBAL_ID}</option>
</select></td>
我不确定我到底错过了什么。请在这件事上给予我帮助。提前致谢。如果我提供了足够的信息或者是否需要更多信息，请告诉我。 再次感谢
最佳答案
您是否错过了导入类(class)？
<%@ page import="master.dao.util.MasterDataConstants" %>
在与每个常量相对应的MasterDataConstants类中创建getter方法。
例如如下所示。对其他人也采取同样的方式。
MasterDataConstants.java
public static final String DIVISION_TYPE_DROPDOWN_AUDIT_MANAGEMENT_GLOBAL_ID = "Audit Management - Global";
public String getDIVISION_TYPE_DROPDOWN_AUDIT_MANAGEMENT_GLOBAL_ID() {
return DIVISION_TYPE_DROPDOWN_AUDIT_MANAGEMENT_GLOBAL_ID;
}
JSP:
${masterDaoUtil.getDIVISION_TYPE_DROPDOWN_AUDIT_MANAGEMENT_GLOBAL_ID()}
关于java - 在 JSP 下拉菜单中调用常量，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/23875883/