日期:2014-05-18  浏览次数:20734 次

jsp2.0表达式问题
相同的一个jsp文件,含有表达式的计算,为什么放在tomcat目录下的webapps目录下的任意应用程序目录下执行都可以得到正确的结果,如果应用程序目录不在tomcat目下的webapps下,执行就不会计算表达式,代码如下:
<!--
    Copyright   2004   The   Apache   Software   Foundation

    Licensed   under   the   Apache   License,   Version   2.0   (the   "License ");
    you   may   not   use   this   file   except   in   compliance   with   the   License.
    You   may   obtain   a   copy   of   the   License   at

            http://www.apache.org/licenses/LICENSE-2.0

    Unless   required   by   applicable   law   or   agreed   to   in   writing,   software
    distributed   under   the   License   is   distributed   on   an   "AS   IS "   BASIS,
    WITHOUT   WARRANTIES   OR   CONDITIONS   OF   ANY   KIND,   either   express   or   implied.
    See   the   License   for   the   specific   language   governing   permissions   and
    limitations   under   the   License.
-->
<html>
    <head>
        <title> JSP   2.0   Expression   Language   -   Basic   Arithmetic </title>
    </head>
    <body>
        <h1> JSP   2.0   Expression   Language   -   Basic   Arithmetic </h1>
        <hr>
        This   example   illustrates   basic   Expression   Language   arithmetic.
        Addition   (+),   subtraction   (-),   multiplication   (*),   division   (/   or   div),  
        and   modulus   (%   or   mod)   are   all   supported.     Error   conditions,   like
        division   by   zero,   are   handled   gracefully.
        <br>
        <blockquote>
            <code>
                <table   border= "1 ">
                    <thead>
        <td> <b> EL   Expression </b> </td>
        <td> <b> Result </b> </td>
    </thead>
    <tr>
        <td> \${1} </td>
        <td> ${1} </td>
    </tr>
    <tr>
        <td> \${1   +   2} </td>
        <td> ${1   +   2} </td>
    </tr>
    <tr>
        <td> \${1.2   +   2.3} </td>
        <td> ${1.2   +   2.3}