HttpServer服务器，处理请求的基本原理

时间 2019-11-20

原文原文链接

大部分框架在对Http请求封装的基础原理为：html

截取URL请求java
在web.xml中配置一个Servlet或者Filter，配置须要截取的url，好比struts1是在web.xml文件中配置截取.do的全部请求。web
解析参数，从新封装 app
经过继承HttpServlet，加载并启动全部用户自定义服务，加载全部用户自定义业务处理Action配置框架
经过HttpServlet中的init()方法中的ServletConfig获取上下文ServletContextjsp
经过HttpServlet中的service()方法中的ServletRequest和ServletResponse入参，能够控制本次链接的输入输出ide
HttpServletRequest的request.getParameterNames()方法能够获得全部的参数post
获取请求URI并进行转向测试
HttpServletRequest的hRequest.getRequestURI()和 hRequest.getContextPath();方法能够获取本次请求的URI，根据URI能够将这次请求转向一个固定的业务处理行为ui
最后，作destroy的时候须要考虑释放全部的资源，特别是用户启动的服务

样本：

get请求和返回：

GET /testupload/file_upload_javabean_form1.jsp?test=11123 HTTP/1.1
Accept: image/jpeg, application/x-ms-application, image/gif, application/xaml+xml, image/pjpeg, application/x-ms-xbap, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
Accept-Language: zh-Hans-CN,zh-Hans;q=0.8,en-US;q=0.5,en;q=0.3
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.2; WOW64; Trident/6.0)
Accept-Encoding: gzip, deflate
Host: 127.0.0.1:1111
Connection: Keep-Alive
Cookie: JSESSIONID=1rc5wzqgboec02hogbehpjs88

HTTP/1.1 200 OK
Date: Tue, 20 May 2014 14:52:35 GMT
Content-Type: text/html; charset=gb2312
Content-Length: 853
Server: Jetty(8.0.4.v20111024)

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
  <meta http-equiv="Content-Type" content="text/html; charset=gb2312">
  <title>文件上传</title>
 </head>
 <body>
  <h1 align="center">文件上传</h1>
  <FORM NAME="form1" METHOD="POST" ACTION="file_upload_javabean_do.jsp">
    <table width="80%" border="0" align="center" >
   <tr> 
     <td height="30" width="50%" align="right">请选择要上传的文件：</td>
     <td height="30" width="50%" align="left"><input type="input" name="file" size="30" value="111"></td>
   </tr>  
   <tr> 
     <td colspan="2" height="30" align="center">
     <input type="submit" name="Sub" value="上传">
     &nbsp;&nbsp;
     <input type="reset" name="Res" value="重选">
    </td>
   </tr>
    </table>
  </FORM>
 </body>
</html>

post文件上传请求和返回

POST /testupload/file_upload_javabean_do.jsp HTTP/1.1
Accept: image/jpeg, application/x-ms-application, image/gif, application/xaml+xml, image/pjpeg, application/x-ms-xbap, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
Referer: http://127.0.0.1:1111/testupload/file_upload_javabean_form.jsp
Accept-Language: zh-Hans-CN,zh-Hans;q=0.8,en-US;q=0.5,en;q=0.3
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.2; WOW64; Trident/6.0)
Content-Type: multipart/form-data; boundary=---------------------------7de776203f0
Accept-Encoding: gzip, deflate
Host: 127.0.0.1:1111
Content-Length: 280
Connection: Keep-Alive
Cache-Control: no-cache
Cookie: JSESSIONID=1qnwmkj0juw6w1epld6xbloicx
 
-----------------------------7de776203f0
Content-Disposition: form-data; name="file"; filename="111.txt"
Content-Type: text/plain
12345
-----------------------------7de776203f0
Content-Disposition: form-data; name="Sub"
上传
-----------------------------7de776203f0--

  
HTTP/1.1 200 OK
Date: Tue, 20 May 2014 14:47:06 GMT
Set-Cookie: JSESSIONID=1rc5wzqgboec02hogbehpjs88;Path=/
Expires: Thu, 01 Jan 1970 00:00:00 GMT
Content-Type: text/plain;charset=gb2312
Content-Length: 335
Server: Jetty(8.0.4.v20111024)
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
  <meta http-equiv="Content-Type" content="text/html; charset=gb2312">
  <title>上传文件</title>
 </head>
 <body>
 <h1 align=center>文件 <font color=red>111.txt</font> 上传成功！</h1>
 </body>
</html>

基本post请求

POST /testupload/file_upload_javabean_do1.jsp HTTP/1.1
Accept: image/jpeg, application/x-ms-application, image/gif, application/xaml+xml, image/pjpeg, application/x-ms-xbap, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
Referer: http://127.0.0.1:1111/testupload/file_upload_javabean_form1.jsp?test=11123
Accept-Language: zh-Hans-CN,zh-Hans;q=0.8,en-US;q=0.5,en;q=0.3
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.2; WOW64; Trident/6.0)
Content-Type: application/x-www-form-urlencoded
Accept-Encoding: gzip, deflate
Host: 127.0.0.1:1111
Content-Length: 32
Connection: Keep-Alive
Cache-Control: no-cache
Cookie: JSESSIONID=1rc5wzqgboec02hogbehpjs88
 
data=4321&Sub=%E4%B8%8A%E4%BC%A0

  
HTTP/1.1 200 OK
Date: Tue, 20 May 2014 15:02:20 GMT
Content-Type: text/html;charset=UTF-8
Content-Length: 290
Server: Jetty(8.0.4.v20111024)
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
  <meta http-equiv="Content-Type" content="text/html; charset=gb2312">
  <title>测试页面</title>
 </head>
 <body>
 
 
 <div>4321</div>
 </body>
</html>