request應用-請求頭學習筆記

request對象常用API

1）取得請求頭相關的信息
*a)request.getHeader(String):String
b)request.getHeaders(String):Enumeration
c)getHeaderNames():Enumeration

java代碼實現：

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");
        //客戶端接收的語言類型
        String acceptLanguage = response.getHeader("Accept-Language");
        //客戶端版本號的名字
        String userAgent = request.getHeader("User-Agent");
        //連接的目標主機和端口號
        String host = request.getHeader("Host");
        response.getWriter().write("客戶端接收的語言類型 Accept-Language=" + acceptLanguage + "<br/>");
        response.getWriter().write("客戶端版本號的名字 User-Agent=" + userAgent + "<br/>");
        response.getWriter().write("連接的目標主機和端口號 Host=" + host + "<br/>");
        response.getWriter().write("========================================= "+ "<br/>");
        //一次性取得所有的請求頭信息
        Enumeration<String> enums  = request.getHeaderNames();
        while(enums.hasMoreElements())
        {
            //請求頭
            String keys =  enums.nextElement();
            Enumeration<String> enums2 = request.getHeaders(keys);
            while(enums2.hasMoreElements())
            {
                String value = enums2.nextElement();
                response.getWriter().write(keys+"<->"+value+"<br/>");
            }

        }

    }

}