Java web 项目经常需要处理错误的情况，总不可能让服务器的错误就这么抛出来的，这样即不安全，也不美观，看下面例子
<%@ page contentType="text/html; charset=utf-8" language="java" import="java.util.*" errorPage="" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>ERROR</title>
</head>
<body>
<h3>ERROR PAGE</h3>
<!--======start: row 02======-->
<div id="row02" class="doc01">
<table>
<tr>
<td align="left" valign="top">
Error:
</td>
<td style="width:20px;"></td>
<td align="left" class="h20">
<%
//--------------------------------------
//active this code only for develop
//--------------------------------------
Throwable throwable = (Throwable) request.getAttribute("javax.servlet.error.exception");
if(throwable == null){
out.println("<b>4XX/5XX Erro:</b> <p>找不到指定的资源或请求的文件不存在。</p>");
}else{
out.println("<b>4XX/5XX Error: </b> "+throwable);
}
out.print("<p>");
if (throwable != null) {
StackTraceElement[] stackTraceElements = throwable.getStackTrace();
for (int i = 0; i < stackTraceElements.length; i++) {
out.print(stackTraceElements[i].toString() + "<br>");
}
stackTraceElements = null;
}
out.print("</p>");
throwable = null;
%>
</td>
</tr>
</table>
</div>
<!--======end: row 02======-->
<br>
<br>
<h4>page footer</h4>
</body>
</html>
整理一下，呵呵，懒人计划...
