这两天有朋友问我怎么取环境变量，想想以前用PHP，很简单就可以用phpinfo()取到了，JAVA会麻烦一点。找了一下，找到以前收藏过一个例程。
<%@ page session="false" import="java.util.*" %>
<%
String strEnvs[][] =
{
{"CONTENT_LENGTH",String.valueOf(request.getContentLength())},
{"CONTENT_TYPE",request.getContentType()},
{"SERVER_PROTOCOL",request.getProtocol()},
{"SERVER_SOFTWARE",getServletContext().getServerInfo()},
{"REMOTE_ADDR",request.getRemoteAddr()},
{"REMOTE_HOST",request.getRemoteHost()},
{"REMOTE_USER",request.getRemoteUser()},
{"SERVER_NAME",request.getServerName()},
{"SERVER_PORT",String.valueOf(request.getServerPort())},
{"AUTH_TYPE",request.getAuthType()},
{"REQUEST_METHOD",request.getMethod()},
{"PATH_INFO",request.getPathInfo()},
{"PATH_TRANSLATED",request.getPathTranslated()},
{"QUERY_STRING",request.getQueryString()},
{"REQUEST_URI",request.getRequestURI()},
{"SCRIPT_NAME",request.getServletPath()},
{"DOCUMENT_ROOT",getServletContext().getRealPath("/")}
};
Enumeration enumNames;
String strName,strValue;
int i;
%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>JSP例程 - 获取各种CGI环境变量</title>
</head>
<body>
<table border=1 cellspacing=0 cellpadding=0 align=center>
<tr>
<th>Name</th>
<th>Value</th>
</tr>
<%
enumNames = request.getHeaderNames();
while(enumNames.hasMoreElements()){
strName = (String)enumNames.nextElement();
strValue = request.getHeader(strName);
%>
<tr>
<td> <%=strName%></td>
<td> <%=strValue%></td>
</tr>
<%
}
%>
<tr>
<th>Name</th>
<th>Value</th>
</tr>
<%
for(i=0;i<strEnvs.length;i++){
%>
<tr>
<td> <%=strEnvs[i][0]%></td>
<td> <%=strEnvs[i][1]%></td>
</tr>
<%
}
%>
</table>
</body>
</html>