Question

我在JSTL文件中有下一个代码：

<c:choose>
    <c:when test="${application.lodging eq 'F'}"><bean:message key="courseapplication.lodgingF"/></c:when>
    <c:when test="${application.lodging eq 'H'}"><bean:message key="courseapplication.lodgingH"/></c:when>
    <c:when test="${application.lodging eq 'B'}"><bean:message key="courseapplication.lodgingB"/></c:when>
</c:choose>

$ application.lodging是F，但我收到了下一个错误：

SEVERE: ServletException in '/administration/jsp/applications.jsp': An exception occured trying to convert String "F" to type "java.lang.Long"
org.apache.jasper.JasperException: Exception in JSP: /administration/jsp/applications.jsp:20

17: <h2><a href="application.do?id=${application.id}&amp;type=S">${application.name}</a></h2>
18: <h3>
19: <c:choose>
20:     <c:when test="${application.lodging eq 'F'}"><bean:message key="courseapplication.lodgingF"/></c:when>
21:     <c:when test="${application.lodging eq 'H'}"><bean:message key="courseapplication.lodgingH"/></c:when>
22:     <c:when test="${application.lodging eq 'B'}"><bean:message key="courseapplication.lodgingB"/></c:when>
23: </c:choose>

在使用Apache Tomcat 6.0的本地服务器中，此代码没有出现任何问题。

在我的应用服务器上使用tomcat 5.5会出现上述错误。

有谁知道为什么会这样？

如果我使用 == 而不是 eq

，也会发生同样的情况

SEVERE: ServletException in '/administration/jsp/applications.jsp': An exception occured trying to convert String "F" to type "java.lang.Long"
org.apache.jasper.JasperException: Exception in JSP: /administration/jsp/applications.jsp:20

17: <h2><a href="application.do?id=${application.id}&amp;type=S">${application.name}</a></h2>
18: <h3>
19: <c:choose>
20:     <c:when test="${application.lodging=='F'}"><bean:message key="courseapplication.lodgingF"/></c:when>
21:     <c:when test="${application.lodging=='H'}"><bean:message key="courseapplication.lodgingH"/></c:when>
22:     <c:when test="${application.lodging=='B'}"><bean:message key="courseapplication.lodgingB"/></c:when>
23: </c:choose>

Answer 1

异常表示application.lodging是数字，而不是字符串。是对的吗？在这种情况下，您可能需要先将“F”，“H”，“B”字符串转换为数字（是否要比较字符？）

Answer 2

您是否尝试对字符串进行简单比较，如suggested in this answer？

<c:when test="${application.lodging=='F'}"><bean:message key="courseapplication.lodgingF"/></c:when>

可能适用于两种环境......

比较字符串时的JSTL异常

2 个答案: