JSTL sql:查询变量

问题描述

我在JSP文件中编写了以下代码:

I wrote the following code in a JSP file:

<c:catch var="e">
    <%
        int accountNumber = Integer.parseInt(request.getParameter("accountNumber"));
        int depositAmount = Integer.parseInt(request.getParameter("depositAmount"));
    %>
    <sql:query var='account' dataSource="jdbc/bank">
        select * from account where AccountNumber=<%= accountNumber %>
    </sql:query>
    <c:choose>
        <c:when test="${account.first() == false}">
            <p>Account not found</p>
        </c:when>
        <c:otherwise>
            <h3>Deposit Made</h3>
            <p>Account number: <%= accountNumber %></p>
            <p>Deposit amount: <%= depositAmount %></p>
            <p>New balance: </p>
        </c:otherwise>
    </c:choose>
</c:catch>


<c:if test="${e != null}">
    error
</c:if>

我遇到的问题是以下代码引发了javax.el.MethodNotFoundException:无法找到具有[0]参数异常的方法[first]:

The problem I am having is that the following code throws an javax.el.MethodNotFoundException: Unable to find method [first] with [0] parameters exception:

<c:when test="${account.first() == false}">
  <p>Account not found</p>
</c:when>

我需要访问sql:query中的account变量，以便检查第一行是否存在.

I need to access the account variable in the sql:query so I can check to see if a first row exists.

推荐答案

<sql:query var='account' dataSource="jdbc/bank">

根据 <sql:query>文档，account是 javax.servlet.jsp.jstl.sql.Result类.

As per the <sql:query> documentation, the account is a javax.servlet.jsp.jstl.sql.Result class.

<c:when test="${account.first() == false}">

根据类的javadoc，该类没有first()方法.但是，有一个 getRowCount()方法.我建议改用它.

As per the class' javadoc, that class doesn't have a first() method. There is however a getRowCount() method. I'd suggest to use that instead.

<c:when test="${account.rowCount == 0}">

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