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: 
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  <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}