HTTP学习

1、学习HTTP简介

概念：超文本传输协议，学习规定了浏览器和服务器之间数据传输规则
HTTP协议特点：
1、学习基于TCP协议：面向连接，学习安全
2、学习基于请求—响应模型的学习：一次请求对应一次响应
3、HTTP协议是学习无状态的协议：对于实物处理没有记忆能力。每次请求响应都是学习独立的
缺点：多次请求间不能共享数据
优点：速度快

2、HTTP—请求数据格式

package first;import java.io.IOException;import java.io.PrintWriter;import java.util.Enumeration;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.jasper.tagplugins.jstl.core.Out;/** * Servlet implementation class Servlet01 */@WebServlet("/Servlet01")public class Servlet01 extends HttpServlet { 	private static final long serialVersionUID = 1L;           /**     * @see HttpServlet#HttpServlet()     */    public Servlet01() {         super();        // TODO Auto-generated constructor stub    }	/**	 * @see HttpServlet#doGet(HttpServletRequest request,学习 HttpServletResponse response)	 */	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 		// TODO Auto-generated method stub		//response.getWriter().append("Served at: ").append(request.getContextPath());		String account=request.getParameter("account");		String psd=request.getParameter("psd");		PrintWriter out=response.getWriter();		out.println(account);		out.println(psd);		Enumerationheaders=request.getHeaderNames();		response.setContentType("text/html;charset=utf_8");		while(headers.hasMoreElements()) { 			String header_name=headers.nextElement();			String header_value=request.getHeader(header_name);			out.println(""+header_name+":"+header_value+"h1");		}		out.println("
"+request.getRemoteAddr()+"");	}	/**	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)	 */	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 		// TODO Auto-generated method stub		doGet(request, response);	}}

host:localhost:8080h1
connection:keep-aliveh1
content-length:19h1
cache-control:max-age=0h1
sec-ch-ua:"Microsoft Edge";v="105", " Not;A Brand";v="99", "Chromium";v="105"h1
sec-ch-ua-mobile:?0h1
sec-ch-ua-platform:"Windows"h1
upgrade-insecure-requests:1h1
origin:http://localhost:8080h1
content-type:application/x-www-form-urlencodedh1
user-agent:Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36 Edg/105.0.1343.42h1
accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9h1
sec-fetch-site:same-originh1
sec-fetch-mode:navigateh1
sec-fetch-user:?1h1
sec-fetch-dest:documenth1
referer:http://localhost:8080/Chapter1/firstJSP.jsph1
accept-encoding:gzip, deflate, brh1
accept-language:zh-CN,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6h1
cookie:JSESSIONID=AD727F0589AD364C4C9ED5FF777CC4DFh1
0:0:0:0:0:0:0:1

请求数据的3部分：
请求行：请求数据的第一行（get：请求方式，/表示请求资源路径，学习HTTP/1.1表示协议版本）
请求头：第二行开始（格式为key：value形式）
3. 请求体：POST请求的学习最后一部分（存放请求参数）

GET请求和POST请求的区别：
1、GET：请求参数在请求行中，学习没有请求体
POST：请求在请求体
2、学习GET请求：参数大小有限制