通过JSTL代码在JavaScript中设置数组值 [英] Set array values in javascript from JSTL code

问题描述

我有一个看起来像这样的代码:

在AnalyzeUserClient.jsp中:

I have a code that looks like this:

In AnalyzeUserClient.jsp:

<c:set var="arrayList"><%= (ArrayList<String>)request.getSession().getAttribute("arrayList") %></c:set>
var sessionId = [];
<c:forEach items=${arrayList} var="id">
sessionId.push("${id}"); // add them one at a time, assuming string values
</c:forEach>

但是，这一行:

    sessionId.push("${id}");

似乎没有将值传递到数组"sessionId"中(我在浏览器上查看了源代码).所以问题是，我应该怎么做才能将值传递到数组中?

我刚刚意识到存在一些问题，因为JSTL是服务器端的，而JavaScript是客户端的.所以有没有解决的办法?

does not seem to be passing the values into the array "sessionId" (I viewed the source code on browser).So the question is,what can I do to pass the values into the array?

I just realised that there are some problems as JSTL is server-side and JavaScript is client-side.So is there a workaround on it?

推荐答案

请勿混合使用EL和脚本.实际上，完全不用考虑scriptlet:

Don't mix EL and scriptlets. In fact, forget about scriptlets completely:

var sessionId = [];
<c:forEach items="${sessionScope.arrayList}" var="id">
    sessionId.push("${id}"); 
</c:forEach>

请注意，如果其中一个ID恰好包含双引号，则会生成无效的JavaScript.因此，最好先在控制器中使用JavaScript转义ID.我建议一种完全不同的方法:在控制器中将ID列表序列化为JSON字符串，然后将此JSON字符串存储在request属性中. JSP页面将只需要

Note though that this will generate invalid JavaScript if one of the IDs happens to contain a double quote. So you'd better JavaScript-escape the IDs before, in your controller. And I would suggest a completely different approach: serialize the list of IDs to a JSON string in your controller, and store this JSON string in request attribute. The JSP page will just need

var sessionId = ${jsonEncodedSessionIds};

它将转换为以下生成的代码:

which will translate to the following generated code:

var sessionId = ["id1", "id2"];

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