如何使用count和JSTL ForEach动态地创建表 [英] How to create table dynamically using count and JSTL ForEach

问题描述

我想创建一个动态表，接受书属性，当它提供了否。要在前一页输入的书籍。
但我没有收到任何东西。

这是我的代码：

 <表> 
< c：forEach begin =1end =$ {no}step =1varStatus =loopCounter> 
< tr> 
< td> 
< input type ='text'name =isbnplaceholder =ISBN> 
< / td> 
< td> 
< input type =textname =Titleplaceholder =Title> 
< / td> 
< td> 
< input type =textname =Authorsplaceholder =Author> 
< / td> 
< td> 
< input type =textname =Versionplaceholder =Version> 
< / td> 
< / tr> 
< / c：forEach> 
< / table> 
  

$ {no}是我想要输入的书数。
我是新来的。对不起，如果标题不清楚。请帮助。

解决方案

你没有得到任何东西，因为你没有迭代你的书籍列表。另外，在每次迭代中，您只打印大量< input type =text/> 。你的代码应该是这样的（假设你的书籍列表是 lstBooks ，它已经被初始化了）：

 <表> 
 <！ - 这里应该有一些标题...  - > 
< tr> 
< th> ISBN< / th> 
< th>标题< / th> 
< th>作者< / th> 
< th>版本< / th> 
< / tr> 
< c：forEach begin =1end =$ {no}step =1varStatus =loopCounter
 value =$ {lstBooks}var =book> ; 
< tr> 
< td> 
< c：out value =$ {book.isbn}/> 
< / td> 
< td> 
< c：out value =$ {book.title}/> 
< / td> 
< td> 
< c：out value =$ {book.authors}/> 
< / td> 
< td> 
< c：out value =$ {book.version}/> 
< / td> 
< / tr> 
< / c：forEach> 
< / table> 
  

---

在根据评论了解您的问题后， $ {no} 变量在 request.getAttribute（no）中可用。你可以使用scriptlet来测试（但这是一个坏主意），或者只是使用< ; c：out value =$ {no}/> 。

注意，正如我所说的，变量应该是可通过 request.getAttribute 访问，请勿将其与 request.getParameter 混淆。

顺便说一句，如果你知道哪个值是这样的话，你可以设置一个变量：

pre $ < c：set var =novalue =10/>


然后您可以使用 $ {no} 。

更多信息 JSTL核心标签

I want to create a dynamic table accepting book attributes when it has provided the no. of books to be entered on the previous page. But I am not getting anything.

This is my code:

<table>
<c:forEach begin="1" end= "${ no }" step="1" varStatus="loopCounter">
<tr>
<td>
<input type='text' name="isbn" placeholder="ISBN">
</td>
<td>
<input type="text" name="Title" placeholder="Title">
</td>
<td>
<input type="text" name="Authors" placeholder="Author">
</td>
<td>
<input type="text" name="Version" placeholder="Version">
</td>
</tr>
</c:forEach>
</table>

${no} is the count of number of books I want to enter. I am new here. Sorry if the title is not clear. Please help.

解决方案

You're not getting anything because you're not iterating your list of books. Also, you're only printing lots of <input type="text" /> on each iteration. Your code should look like this (assuming that your list of books is lstBooks and it's already initialized):

<table>
    <!-- here should go some titles... -->
    <tr>
        <th>ISBN</th>
        <th>Title</th>
        <th>Authors</th>
        <th>Version</th>
    </tr>
    <c:forEach begin="1" end= "${ no }" step="1" varStatus="loopCounter"
        value="${lstBooks}" var="book">
    <tr>
        <td>
            <c:out value="${book.isbn}" />
        </td>
        <td>
            <c:out value="${book.title}" />
        </td>
        <td>
            <c:out value="${book.authors}" />
        </td>
        <td>
            <c:out value="${book.version}" />
        </td>
    </tr>
    </c:forEach>
</table>

---

After understanding your problem based on comments, make sure the ${no} variable is available at request.getAttribute("no"). You can test this using a scriptlet (but this is a bad idea) or just using <c:out value="${no}" />.

Note that as I've said, the variable should be accesible through request.getAttribute, do not confuse it with request.getParameter.

By the way, you can set a variable if you know which could be it's value like this:

<c:set var="no" value="10" />

And then you can access to it using ${no}.

More info: JSTL Core Tag

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