request应用-请求头学习笔记

request对象常用API

1）取得请求头相关的信息
*a)request.getHeader(String):String
b)request.getHeaders(String):Enumeration
c)getHeaderNames():Enumeration

java代码实现：

import java.io.IOException;import java.io.PrintWriter;import java.util.Enumeration;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class Rdome2 extends HttpServlet {    public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        response.setCharacterEncoding("utf-8");        //客户端接收的语言类型        String acceptLanguage = response.getHeader("Accept-Language");        //客户端版本号的名字        String userAgent = request.getHeader("User-Agent");        //连接的目标主机和端口号        String host = request.getHeader("Host");        response.getWriter().write("客户端接收的语言类型 Accept-Language=" + acceptLanguage + "<br/>");        response.getWriter().write("客户端版本号的名字 User-Agent=" + userAgent + "<br/>");        response.getWriter().write("连接的目标主机和端口号 Host=" + host + "<br/>");        response.getWriter().write("========================================= "+ "<br/>");        //一次性取得所有的请求头信息        Enumeration<String> enums  = request.getHeaderNames();        while(enums.hasMoreElements())        {            //请求头            String keys =  enums.nextElement();            Enumeration<String> enums2 = request.getHeaders(keys);            while(enums2.hasMoreElements())            {                String value = enums2.nextElement();                response.getWriter().write(keys+"<->"+value+"<br/>");            }        }    }}