java JSP 中的 ArrayList 到表
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ArrayList to Table in JSP
提问by Dave
I have an ArrayList and i am trying to display it in a table
我有一个 ArrayList 并且我试图将它显示在表格中
.....
.....
ArrayList rows = ....
ArrayList 行 = ....
.....
.....
<table cellspacing="1" cellpadding="4" border="3">
<tr>
<TH>
Heading1
</TH>
<TH>
Heading2
</TH>
<TH>
Heading3
</TH>
<TH>
Heading4
</TH>
<TH>
Heading5
</TH>
<TH>
Heading6
</TH>
<TH>
Heading7
</TH>
</tr>
<tr>
<% for (int i = 0; i < rows.size(); i++) {
for (int j = 0; j < 7; j++) {
%>
<td>
<center>
<% out.println( ????? ); %>
</center>
</td>
<% } %>
</tr>
<% } %>
</table>
but i am having trouble displaying the correct data.
但我无法显示正确的数据。
回答by Andrzej Doyle
Well for one thing, I suspect that your outer loop should start above the <tr>tag.
一方面，我怀疑您的外循环应该从<tr>标签上方开始。
Other than that, an ArrayList is a one-dimensional structure (not surprisingly, since it's a list). Trying to display this data in a table implies it's two dimensional, but without generics you've given no information as to what's contained within the list.
除此之外，ArrayList 是一个一维结构（毫不奇怪，因为它是一个列表）。尝试在表格中显示此数据意味着它是二维的，但如果没有泛型，您将无法提供有关列表中包含的内容的信息。
I'd approach this something like this:
我会这样处理：
/* header rows */
<% for (int i = 0; i < rows.size(); i++) {
Object rowObj = rows.get(i);
%>
<tr>
<% for (int j = 0; j < 7; j++) {
// This RHS made up due to not knowing the class of objects
// in your map, use something equivalent
Object cell = rowObj.getEntry(j);
%>
<td>
<center>
<%=cell.toString()%>
</center>
</td>
<% } %>
</tr>
<% } %>
回答by BalusC
You should not use scriptlets for this. Use JSTL/EL for this. Shortly back I've posted an example, you can find here: Places where JavaBeans are used?
您不应该为此使用 scriptlet。为此使用 JSTL/EL。不久前，我发布了一个示例，您可以在这里找到：使用 JavaBean 的地方？
回答by Kelly S. French
It's a perfect scenario for using JSP taglibs. There is a huge list of available tablibs over at jsptags.comThat way the HTML will be very readable but you'll have your dynamic table.
这是使用 JSP 标记库的完美场景。有超过可用tablibs在一个巨大的名单jsptags.com这样的HTML将是非常具有可读性，但你有你的动态表。
回答by Vincent Ramdhanie
As others have pointed out you would want to use tags rather than generate a table yourself using scriptlets. The benefits are more than I care to list here. I would recommend looking at the Display tag library. It makes it trivially easy to generate a table from any Collection.
正如其他人指出的那样，您希望使用标签而不是使用 scriptlet 自己生成表格。好处比我想在这里列出的要多。我建议查看Display tag library。它使从任何集合生成表变得非常容易。
<display:table name="rows">
<display:column property="id" title="ID" />
<display:column property="name" />
<display:column property="email" />
<display:column property="status" />
<display:column property="description" title="Comments"/>
</display:table>
Of course each column would refer to a property of the objects that you have in your ArrayList.
当然，每一列都将引用您在 ArrayList 中拥有的对象的一个属性。
回答by Alexander Pavloshchuk
You may use core JSTL library (download it from http://jakarta.apache.org/site/downloads/downloads_taglibs.html).
您可以使用核心 JSTL 库（从http://jakarta.apache.org/site/downloads/downloads_taglibs.html下载）。
Include jstl.jar and standard.jar libraries from this distribution into you class path. Then place directive <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>on top of your jsp-file. And use construction like this:
将此发行版中的 jstl.jar 和 standard.jar 库包含到您的类路径中。然后将指令<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>放在 jsp 文件的顶部。并使用这样的构造：
...
<br/>
<table><br/>
<c:forEach items="${rows}" var="row"><br/>
<tr><br/>
<c:forEach items="${row}" var="column"><br/>
<td><br/>
<c:out value="${column}"/><br/>
</td><br/>
</c:forEach><br/>
</tr><br/>
</c:forEach><br/>
</table><br/>
...
