我们经常会用python来进行抓包，模拟登陆等等， 势必要构造http请求包。 http的request通常有4个方法get，post，put，delete，分别对应于查询，更新，添加，删除。我们经常用到的也就get，post。 1.用python构造get #build request for accessed url     homeReq = urllib.request.Request(          url = csdnAccessModuleUrl          )     homeReq.add_header('Accept', 'text/html, application/xhtml+xml, */*');     homeReq.add_header('Accept-Language', 'en-US')     homeReq.add_header('Accept-Encoding', 'gzip, deflate')     homeReq.add_header('Connection', 'Keep-Alive');     homeReq.add_header('Referer', 'http://passport.csdn.net/account/login?from='+urllib.parse.quote(moduleUrl))#http%3a%2f%2fwrite.blog.csdn.net%2f')     homeReq.add_header('User-Agent', 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)');     #open access url     resp = urllib.request.urlopen(homeReq) 2.用python构造post #build request for login url     #post data     postdata = {         'u':username,         'p':password,         'remember':'1',         't':'log',         'f':urllib.parse.quote(moduleUrl),         }     postdata = urllib.parse.urlencode(postdata).encode('utf-8')     print(postdata)     req = urllib.request.Request(          url = csdnLoginUrl,          data = postdata)     req.add_header('Accept', 'text/html, application/xhtml+xml, */*');     req.add_header('Accept-Language', 'en-US')     req.add_header('Accept-Encoding', 'gzip, deflate')     req.add_header('Connection', 'Keep-Alive');     req.add_header('Referer', csdnAccessModuleUrl)     req.add_header('User-Agent', 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)');     #open login url     r = urllib.request.urlopen(req) 通过上面2个例子我们可以发现， 当Request的postdata赋值时，则为post方法，默认为get。