HTTP学习笔记

<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: small;"><span lang="EN-US"><span style="font-family: Times New Roman;">HTTP</span></span><span style="">学习笔记</span></span></p>
<p class="MsoNormal" style=""><span style="font-family: Times New Roman;"><span style="" lang="EN-US"><span style=""><span style="font-size: small;">1，</span><span style='font: 7pt "Times New Roman";'> </span></span></span><span lang="EN-US"><span style="font-size: small;">HTTP</span></span></span><span style="font-size: small;"><span style="">是一个基于请求</span><span lang="EN-US"><span style="font-family: Times New Roman;">/</span></span><span style="">响应的，无状态的应用层协议。其底层是</span><span lang="EN-US"><span style="font-family: Times New Roman;">TCP</span></span><span style="">协议。</span></span></p>
<p class="MsoNormal" style=""><span style="" lang="EN-US"><span style=""><span style="font-family: Times New Roman;"><span style="font-size: small;">2，</span><span style='font: 7pt "Times New Roman";'> </span></span></span></span><span style="font-size: small;"><span style="">在</span><span lang="EN-US"><span style="font-family: Times New Roman;">HTTP V1.0</span></span><span style="">协议中，每一次请求</span><span lang="EN-US"><span style="font-family: Times New Roman;">/</span></span><span style="">响应都必须建立和关闭一次网络连接。但是在</span><span lang="EN-US"><span style="font-family: Times New Roman;">HTTPV1.1</span></span><span style="">中，每一次</span><span lang="EN-US"><span style="font-family: Times New Roman;">HTTP</span></span><span style="">连接建立以后，可以连续进行多次请求和应答，客户端甚至可以发起流水请求。</span></span></p>
<p class="MsoNormal" style=""><span style="font-family: Times New Roman;"><span style="" lang="EN-US"><span style=""><span style="font-size: small;">3，</span><span style='font: 7pt "Times New Roman";'> </span></span></span><span lang="EN-US"><span style="font-size: small;">HTTP</span></span></span><span style=""><span style="font-size: small;">请求由三部分组成：请求行，消息报头，请求正文</span></span></p>
<p class="MsoNormal" style=""><span style="" lang="EN-US"><span style=""><span style="font-family: Times New Roman;"><span style="font-size: small;">4，</span><span style='font: 7pt "Times New Roman";'> </span></span></span></span><span style="font-size: small;"><span style="">请求行：请求行以方法符号开头，后面跟着请求</span><span lang="EN-US"><span style="font-family: Times New Roman;">URI</span></span><span style="">和协议的版本以</span><span lang="EN-US"><span style="font-family: Times New Roman;">CRLF</span></span><span style="">作为结尾，以空格分割。例如：</span><span lang="EN-US"><span style="font-family: Times New Roman;">GET /index.html HTTP/1.1 </span></span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt 18pt;"><span style="font-size: small;"><span style="">目前</span><span lang="EN-US"><span style="font-family: Times New Roman;">HTTP</span></span><span style="">请求共支持</span><span lang="EN-US"><span style="font-family: Times New Roman;">GET POST DELETE CONNECT HEAD PUT TRACE OPTIONS</span></span><span style="">等方法，区分大小写。</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt 18pt;"><span style="font-size: small;"><span lang="EN-US"><span style="font-family: Times New Roman;">GET</span></span><span style="">方法用于请求</span><span style="font-family: Times New Roman;"> </span><span style="">在请求行中标明的</span><span lang="EN-US"><span style="font-family: Times New Roman;">URL</span></span><span style="">的信息。</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt 18pt;"><span style="font-size: small;"><span lang="EN-US"><span style="font-family: Times New Roman;">POST</span></span><span style="">方法用于向服务器端发送数据。</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt 18pt;"><span style="font-size: small;"><span lang="EN-US"><span style="font-family: Times New Roman;">HEAD</span></span><span style="">方法通常用来检查超链接的有效性，最近有没有被更新等。</span></span></p>
<p class="MsoNormal" style=""><span style="font-family: Times New Roman;"><span style="" lang="EN-US"><span style=""><span style="font-size: small;">5，</span><span style='font: 7pt "Times New Roman";'> </span></span></span><span lang="EN-US"><span style="font-size: small;">GET</span></span></span><span style="font-size: small;"><span style="">方法和</span><span lang="EN-US"><span style="font-family: Times New Roman;">POST</span></span><span style="">方法的区别：</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt 18pt;"><span style="font-size: small;"><span style="">方法的目的不同：</span><span lang="EN-US"><span style="font-family: Times New Roman;">GET</span></span><span style="">用于请求资源，</span><span lang="EN-US"><span style="font-family: Times New Roman;">POST</span></span><span style="">用于向服务器输送数据</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt 18pt;"><span style="font-size: small;"><span style="">请求报文的格式不同：</span><span lang="EN-US"><span style="font-family: Times New Roman;">GET</span></span><span style="">请求只有请求行，</span><span lang="EN-US"><span style="font-family: Times New Roman;">POSTS</span></span><span style="">请求包括三部分：请求头，消息报头，请求正文。</span></span></p>
<p class="MsoNormal" style=""><span style="" lang="EN-US"><span style=""><span style="font-family: Times New Roman;"><span style="font-size: small;">6，</span><span style='font: 7pt "Times New Roman";'> </span></span></span></span><span style="font-size: small;"><span style="">虽然在</span><span lang="EN-US"><span style="font-family: Times New Roman;">HTML</span></span><span style="">文档中</span><span lang="EN-US"><span style="font-family: Times New Roman;">get</span></span><span style="">方法和</span><span lang="EN-US"><span style="font-family: Times New Roman;">post</span></span><span style="">方法中可以不区分大小写，但是在</span><span lang="EN-US"><span style="font-family: Times New Roman;">HTTP</span></span><span style="">协议的请求行中，必须区分。</span></span></p>
<p class="MsoNormal" style=""><span style="" lang="EN-US"><span style=""><span style="font-family: Times New Roman;"><span style="font-size: small;">7，</span><span style='font: 7pt "Times New Roman";'> </span></span></span></span><span style="font-size: small;"><span style="">服务器在获取到</span><span lang="EN-US"><span style="font-family: Times New Roman;">HTTP</span></span><span style="">请求，并进行解释后会发出</span><span lang="EN-US"><span style="font-family: Times New Roman;">HTTP</span></span><span style="">响应。</span><span lang="EN-US"><span style="font-family: Times New Roman;">HTTP</span></span><span style="">响应由三部分组成：状态行，消息报头，响应正文。</span></span></p>
<p class="MsoNormal" style=""><span style="" lang="EN-US"><span style=""><span style="font-family: Times New Roman;"><span style="font-size: small;">8，</span><span style='font: 7pt "Times New Roman";'> </span></span></span></span><span style="font-size: small;"><span style="">状态行：由协议版本</span><span lang="EN-US"><span style="font-family: Times New Roman;">+</span></span><span style="">文字形式的相应码</span><span lang="EN-US"><span style="font-family: Times New Roman;">+Reason-Phrase+CRLF</span></span><span style="">组成</span></span></p>
<p class="MsoNormal" style=""><span style="" lang="EN-US"><span style=""><span style="font-family: Times New Roman;"><span style="font-size: small;">9，</span><span style='font: 7pt "Times New Roman";'> </span></span></span></span><span style="font-size: small;"><span style="">消息报头：包括普通报头，请求报头，响应报头，实体报头。每一个报头域都由名字</span><span lang="EN-US"><span style="font-family: Times New Roman;">+</span></span><span style="">“：”</span><span lang="EN-US"><span style="font-family: Times New Roman;">+</span></span><span style="">空格</span><span lang="EN-US"><span style="font-family: Times New Roman;">+</span></span><span style="">值</span><span style="font-family: Times New Roman;"> </span><span style="">组成。其中名字与大小写无关。</span></span></p>
<p class="MsoNormal" style=""><span style="" lang="EN-US"><span style=""><span style="font-family: Times New Roman;"><span style="font-size: small;">10，</span><span style='font: 7pt "Times New Roman";'> </span></span></span></span><span style=""><span style="font-size: small;">在普通报头中，有少数报头域应用于所有请求和相应消息，但并不用于被传输的实体，这些报头域只用于传输的消息。</span></span></p>
<p class="MsoNormal" style=""><span style="font-family: Times New Roman;"><span style="" lang="EN-US"><span style=""><span style="font-size: small;">11，</span><span style='font: 7pt "Times New Roman";'> </span></span></span><span lang="EN-US"><span style="font-size: small;">HTTP</span></span></span><span style=""><span style="font-size: small;">消息总结：</span></span></p>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style=""><span style="font-size: small; font-family: Times New Roman;"> </span></span></span></p>
<table class="MsoTableGrid" style="margin: auto auto auto 23.4pt; width: 405pt; border-collapse: collapse;" border="1" cellspacing="0" cellpadding="0" width="540"><tbody>
<tr style="">
<td style="padding-right: 5.4pt; padding-left: 5.4pt; padding-bottom: 0cm; width: 142pt; padding-top: 0cm; background-color: transparent;" width="189" valign="top">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span lang="EN-US"><span style="font-size: small; font-family: Times New Roman;"></span></span></p>
</td>
<td style="padding-right: 5.4pt; padding-left: 5.4pt; padding-bottom: 0cm; border-left: #ece9d8; width: 142.05pt; padding-top: 0cm; background-color: transparent;" width="189" valign="top">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: small;"><span lang="EN-US"><span style="font-family: Times New Roman;">HTTP</span></span><span style="">请求</span></span></p>
</td>
<td style="padding-right: 5.4pt; padding-left: 5.4pt; padding-bottom: 0cm; border-left: #ece9d8; width: 120.95pt; padding-top: 0cm; background-color: transparent;" width="161" valign="top">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: small;"><span lang="EN-US"><span style="font-family: Times New Roman;">HTTP</span></span><span style="">相应</span></span></p>
</td>
</tr>
<tr style="">
<td style="padding-right: 5.4pt; border-top: #ece9d8; padding-left: 5.4pt; padding-bottom: 0cm; width: 142pt; padding-top: 0cm; background-color: transparent;" width="189" valign="top">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style=""><span style="font-size: small;">开始行</span></span></p>
</td>
<td style="padding-right: 5.4pt; border-top: #ece9d8; padding-left: 5.4pt; padding-bottom: 0cm; border-left: #ece9d8; width: 142.05pt; padding-top: 0cm; background-color: transparent;" width="189" valign="top">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style=""><span style="font-size: small;">请求行</span></span></p>
</td>
<td style="padding-right: 5.4pt; border-top: #ece9d8; padding-left: 5.4pt; padding-bottom: 0cm; border-left: #ece9d8; width: 120.95pt; padding-top: 0cm; background-color: transparent;" width="161" valign="top">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style=""><span style="font-size: small;">状态行</span></span></p>
</td>
</tr>
<tr style="">
<td style="padding-right: 5.4pt; border-top: #ece9d8; padding-left: 5.4pt; padding-bottom: 0cm; width: 142pt; padding-top: 0cm; background-color: transparent;" width="189" valign="top">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style=""><span style="font-size: small;">消息报头（可选）</span></span></p>
</td>
<td style="padding-right: 5.4pt; border-top: #ece9d8; padding-left: 5.4pt; padding-bottom: 0cm; border-left: #ece9d8; width: 142.05pt; padding-top: 0cm; background-color: transparent;" width="189" valign="top">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style=""><span style="font-size: small;">消息报头</span></span></p>
</td>
<td style="padding-right: 5.4pt; border-top: #ece9d8; padding-left: 5.4pt; padding-bottom: 0cm; border-left: #ece9d8; width: 120.95pt; padding-top: 0cm; background-color: transparent;" width="161" valign="top">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style=""><span style="font-size: small;">消息报头</span></span></p>
</td>
</tr>
<tr style="">
<td style="padding-right: 5.4pt; border-top: #ece9d8; padding-left: 5.4pt; padding-bottom: 0cm; width: 142pt; padding-top: 0cm; background-color: transparent;" width="189" valign="top">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style=""><span style="font-size: small;">消息正文（可选）</span></span></p>
</td>
<td style="padding-right: 5.4pt; border-top: #ece9d8; padding-left: 5.4pt; padding-bottom: 0cm; border-left: #ece9d8; width: 142.05pt; padding-top: 0cm; background-color: transparent;" width="189" valign="top">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style=""><span style="font-size: small;">请求正文</span></span></p>
</td>
<td style="padding-right: 5.4pt; border-top: #ece9d8; padding-left: 5.4pt; padding-bottom: 0cm; border-left: #ece9d8; width: 120.95pt; padding-top: 0cm; background-color: transparent;" width="161" valign="top">
<p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style=""><span style="font-size: small;">响应正文</span></span></p>
</td>
</tr>
</tbody></table>
<p class="MsoNormal" style="margin: 0cm 0cm 0pt; text-indent: 17.95pt;"><span style=""><span style="font-size: small;">不同部分之间换行分割。</span></span></p>