如何在JSP中将服务器端变量传递到核心标记中? [英] How can I pass a server side variable into a core tag in JSP?

问题描述

此表达标签对我来说是正确的值 <％= drug.NonAuthoritative％>

This expression tag outpus a correct value for me <%=drug.NonAuthoritative%>

我无法恢复药物的价值.非授权用于C标签

while I cant recover the value of drug.NonAuthoritative for use in a C tag

<c:if test="${drug.NonAuthoritative}">&nbsp;<bean:message key="WriteScript.msgNonAuthoritative"></bean:message></c:if>

方法是

public Boolean NonAuthoritative() {
    return nonAuthoritative;
}

推荐答案

有2个问题:

1. 小脚本和EL不在同一范围内. ${drug}中的drug必须与页面，请求，会话或应用程序范围中现有属性的名称匹配.如果要在 scriptlet 中而不是在控制器中准备drug，那么您应该自己将其作为属性放在这些作用域之一中.

1. Scriptlets and EL do not share the same scope. The drug in ${drug} has to match the name of an existing attribute in the page, request, session or application scope. If you're preparing drug in a scriptlet instead of in a controller, then you should put it as an attribute in one of those scopes yourself.

<% 
    Drug drug = new Drug();
    // ...
    request.setAttribute("drug", drug);
%>

---

(Nathan部分回答)， EL 依赖

---

(as partly answered by Nathan), EL relies on Javabeans specification. The ${drug.propertyName} requires a public method getPropertyName() for non-boolean properties or isPropertyName() for boolean properties. So, this should do

public class Drug {

    private boolean nonAuthorative;

    public boolean isNonAuthorative() {
        return nonAuthorative;
    }

    // ...
}

使用

<c:if test="${drug.nonAuthoritative}">

(请注意外壳！)

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