六、访问CGI变量

SERVER_PORT  服务器监听的端口。  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()。  
SERVER_PROTOCOL  请求命令中的协议名字和版本（即HTTP/1.0或HTTP/1.1）。  request.getProtocol()  
SERVER_SOFTWARE  Servlet引擎的名字和版本。  getServletContext().getServerInfo()  


　　 6.3 实例：读取CGI变量

　　 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。

　　 ShowCGIVariables.java
package hall;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;

public class ShowCGIVariables extends HttpServlet {
  public void doGet(HttpServletRequest request,
                    HttpServletResponse response)
      throws ServletException, IOException {
    response.setContentType("text/html");
    PrintWriter out = response.getWriter();
    String[][] variables =
      { { "AUTH_TYPE", request.getAuthType() },
        { "CONTENT_LENGTH", String.valueOf(request.getContentLength()) },
        { "CONTENT_TYPE", request.getContentType() },
        { "DOCUMENT_ROOT", getServletContext().getRealPath("/") },
        { "PATH_INFO", request.getPathInfo() },
        { "PATH_TRANSLATED", request.getPathTranslated() },
        { "QUERY_STRING", request.getQueryString() },
        { "REMOTE_ADDR", request.getRemoteAddr() },
        { "REMOTE_HOST", request.getRemoteHost() },
        { "REMOTE_USER", request.getRemoteUser() },
        { "REQUEST_METHOD", request.getMethod() },
        { "SCRIPT_NAME", request.getServletPath() },
        { "SERVER_NAME", request.getServerName() },
        { "SERVER_PORT", String.valueOf(request.getServerPort()) },
        { "SERVER_PROTOCOL", request.getProtocol() },
        { "SERVER_SOFTWARE", getServletContext().getServerInfo() }