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<title>csdn_六、访问CGI变量</title>
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        <td WIDTH="50%" bordercolor="#FFFFFF" CLASS="t1" bgcolor="#F0F0F0" align="center" nowrap>六、访问CGI变量</td>
       <p> <td WIDTH="50%" bordercolor="#FFFFFF" CLASS="t1" bgcolor="#F0F0F0" align="center" nowrap>作者：仙人掌工作室</td></p>
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              <br>   
六、访问CGI变量<br>

<br>
<br>
　　 6.1 CGI变量概述 <br>
<br>
　　 如果你是从传统的CGI编程转而学习Java Servlet，或许已经习惯了“CGI变量”这一概念。CGI变量汇集了各种有关请求的信息： <br>
<br>
部分来自HTTP请求命令和请求头，例如Content-Length头； <br>
部分来自Socket本身，例如主机的名字和IP地址； <br>
也有部分与服务器安装配置有关，例如URL到实际路径的映射。 <br>
　　 6.2 标准CGI变量的Servlet等价表示 <br>
<br>
　　 下表假定request对象是提供给doGet和doPost方法的HttpServletRequest类型对象。 CGI变量&nbsp;&nbsp;含义&nbsp;&nbsp;从doGet或doPost访问&nbsp;&nbsp;<br>
AUTH_TYPE&nbsp;&nbsp;如果提供了Authorization头，这里指定了具体的模式（basic或者digest）。&nbsp;&nbsp;request.getAuthType()&nbsp;&nbsp;<br>
CONTENT_LENGTH&nbsp;&nbsp;只用于POST请求，表示所发送数据的字节数。&nbsp;&nbsp;严格地讲，等价的表达方式应该是String.valueOf(request.getContentLength())（返回一个字符串）。但更常见的是用request.getContentLength()返回含义相同的整数。&nbsp;&nbsp;<br>
CONTENT_TYPE&nbsp;&nbsp;如果指定的话，表示后面所跟数据的类型。&nbsp;&nbsp;request.getContentType()&nbsp;&nbsp;<br>
DOCUMENT_ROOT&nbsp;&nbsp;与http://host/对应的路径。&nbsp;&nbsp;getServletContext().getRealPath(&quot;/&quot;) <br>
注意低版本Servlet规范中的等价表达方式是request.getRealPath(&quot;/&quot;)。 <br>
<br>
HTTP_XXX_YYY&nbsp;&nbsp;访问任意HTTP头。&nbsp;&nbsp;request.getHeader(&quot;Xxx-Yyy&quot;)&nbsp;&nbsp;<br>
PATH_INFO&nbsp;&nbsp;URL中的附加路径信息，即URL中Servlet路径之后、查询字符串之前的那部分。&nbsp;&nbsp;request.getPathInfo()&nbsp;&nbsp;<br>
PATH_TRANSLATED&nbsp;&nbsp;映射到服务器实际路径之后的路径信息。&nbsp;&nbsp;request.getPathTranslated()&nbsp;&nbsp;<br>
QUERY_STRING&nbsp;&nbsp;这是字符串形式的附加到URL后面的查询字符串，数据仍旧是URL编码的。在Servlet中很少需要用到未经解码的数据，一般使用getParameter访问各个参数。&nbsp;&nbsp;request.getQueryString()&nbsp;&nbsp;<br>
REMOTE_ADDR&nbsp;&nbsp;发出请求的客户机的IP地址。&nbsp;&nbsp;request.getRemoteAddr()&nbsp;&nbsp;<br>
REMOTE_HOST&nbsp;&nbsp;发出请求的客户机的完整的域名，如java.sun.com。如果不能确定该域名，则返回IP地址。&nbsp;&nbsp;request.getRemoteHost()&nbsp;&nbsp;<br>
REMOTE_USER&nbsp;&nbsp;如果提供了Authorization头，则代表其用户部分。它代表发出请求的用户的名字。&nbsp;&nbsp;request.getRemoteUser()&nbsp;&nbsp;<br>
REQUEST_METHOD&nbsp;&nbsp;请求类型。通常是GET或者POST。但偶尔也会出现HEAD，PUT， DELETE，OPTIONS，或者 TRACE.&nbsp;&nbsp;request.getMethod()&nbsp;&nbsp;<br>
SCRIPT_NAME&nbsp;&nbsp;URL中调用Servlet的那一部分，不包含附加路径信息和查询字符串。&nbsp;&nbsp;request.getServletPath()&nbsp;&nbsp;<br>
SERVER_NAME&nbsp;&nbsp;Web服务器名字。&nbsp;&nbsp;request.getServerName()&nbsp;&nbsp;<br>
SERVER_PORT&nbsp;&nbsp;服务器监听的端口。&nbsp;&nbsp;严格地说，等价表达应该是返回字符串的String.valueOf(request.getServerPort())。但经常使用返回整数值的request.getServerPort()。&nbsp;&nbsp;<br>
SERVER_PROTOCOL&nbsp;&nbsp;请求命令中的协议名字和版本（即HTTP/1.0或HTTP/1.1）。&nbsp;&nbsp;request.getProtocol()&nbsp;&nbsp;<br>
SERVER_SOFTWARE&nbsp;&nbsp;Servlet引擎的名字和版本。&nbsp;&nbsp;getServletContext().getServerInfo()&nbsp;&nbsp;<br>
<br>
<br>
　　 6.3 实例：读取CGI变量 <br>
<br>
　　 下面这个Servlet创建一个表格，显示除了HTTP_XXX_YYY之外的所有CGI变量。HTTP_XXX_YYY是HTTP请求头信息，请参见上一节介绍。 <br>
<br>
　　 ShowCGIVariables.java <br>
package hall;<br>
<br>
import java.io.*;<br>
import javax.servlet.*;<br>
import javax.servlet.http.*;<br>
import java.util.*;<br>
<br>
public class ShowCGIVariables extends HttpServlet {<br>
&nbsp;&nbsp;public void doGet(HttpServletRequest request,<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;HttpServletResponse response)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;throws ServletException, IOException {<br>
&nbsp;&nbsp;&nbsp;&nbsp;response.setContentType(&quot;text/html&quot;);<br>
&nbsp;&nbsp;&nbsp;&nbsp;PrintWriter out = response.getWriter();<br>
&nbsp;&nbsp;&nbsp;&nbsp;String[][] variables =<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ { &quot;AUTH_TYPE&quot;, request.getAuthType() },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;CONTENT_LENGTH&quot;, String.valueOf(request.getContentLength()) },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;CONTENT_TYPE&quot;, request.getContentType() },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;DOCUMENT_ROOT&quot;, getServletContext().getRealPath(&quot;/&quot;) },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;PATH_INFO&quot;, request.getPathInfo() },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;PATH_TRANSLATED&quot;, request.getPathTranslated() },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;QUERY_STRING&quot;, request.getQueryString() },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;REMOTE_ADDR&quot;, request.getRemoteAddr() },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;REMOTE_HOST&quot;, request.getRemoteHost() },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;REMOTE_USER&quot;, request.getRemoteUser() },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;REQUEST_METHOD&quot;, request.getMethod() },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;SCRIPT_NAME&quot;, request.getServletPath() },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;SERVER_NAME&quot;, request.getServerName() },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;SERVER_PORT&quot;, String.valueOf(request.getServerPort()) },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;SERVER_PROTOCOL&quot;, request.getProtocol() },<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{ &quot;SERVER_SOFTWARE&quot;, getServletContext().getServerInfo() }<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;};<br>
&nbsp;&nbsp;&nbsp;&nbsp;String title = &quot;显示CGI变量&quot;;<br>
&nbsp;&nbsp;&nbsp;&nbsp;out.println(ServletUtilities.headWithTitle(title) +<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&quot;＜BODY BGCOLOR=＼&quot;#FDF5E6＼&quot;＞＼n&quot; +<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&quot;＜H1 ALIGN=CENTER＞&quot; + title + &quot;＜/H1＞＼n&quot; +<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&quot;＜TABLE BORDER=1 ALIGN=CENTER＞＼n&quot; +<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&quot;＜TR BGCOLOR=＼&quot;#FFAD00＼&quot;＞＼n&quot; +<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&quot;＜TH＞CGI Variable Name＜TH＞Value&quot;);<br>
&nbsp;&nbsp;&nbsp;&nbsp;for(int i=0; i＜variables.length; i++) {<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;String varName = variables[i][0];<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;String varValue = variables[i][1];<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if (varValue == null)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;varValue = &quot;＜I＞Not specified＜/I＞&quot;;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;out.println(&quot;＜TR＞＜TD＞&quot; + varName + &quot;＜TD＞&quot; + varValue);<br>
&nbsp;&nbsp;&nbsp;&nbsp;}<br>
&nbsp;&nbsp;&nbsp;&nbsp;out.println(&quot;＜/TABLE＞＜/BODY＞＜/HTML＞&quot;);<br>
&nbsp;&nbsp;}<br>
<br>
&nbsp;&nbsp;public void doPost(HttpServletRequest request,<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;HttpServletResponse response)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;throws ServletException, IOException {<br>
&nbsp;&nbsp;&nbsp;&nbsp;doGet(request, response);<br>
&nbsp;&nbsp;}<br>
}      <br>   
      <br>   
        </td>
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      <tr><td colspan=2 align=right class=t> <a href="http://www.chinajavaworld.com/doc/servlet-jsp/32.html" ></a>  <a href="37.html" tppabs="http://www.chinajavaworld.com/doc/servlet-jsp/37.html" ></a> <a href="39.html" tppabs="http://www.chinajavaworld.com/doc/servlet-jsp/39.html" ></a>       </td></tr>
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