用Firebug对POST的数据进行监控 请求 HTTP头 信息,得到如下内容:
Accept application/json, text/javascript, */* Accept-Encoding gzip, deflate Accept-Language en-us,en;q=0.5 Cache-Control no-cache Content-Length 432 Content-Type application/x-www-form-urlencoded; charset=UTF-8 Host www.huaxixiang.com Pragma no-cache Proxy-Connection keep-alive Refere http://www.huaxixiang.com/CrossPriceDetail.action User-Agent Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko/20100101 Firefox/11.0 X-Requested-With XMLHttpRequest
用HttpClient模仿浏览器访问页面,加载URL的HTML信息,为了良好的加载网站的信息,不被限制.
为了说明请求头的信息添加了一个小测试项目LoginTest,添加页面index.jsp,添加主要代码打印Http Header的JSP页面.
主要打印Http Header信息.
1. index.jsp
out.println("Protocol: " + request.getProtocol());
out.println("Scheme: " + request.getScheme());
out.println("Server Name: " + request.getServerName() );
out.println("Server Port: " + request.getServerPort());
out.println("Protocol: " + request.getProtocol());
out.println("Server Info: " + getServletConfig().getServletContext().getServerInfo());
out.println("Remote Addr: " + request.getRemoteAddr());
out.println("Remote Host: " + request.getRemoteHost());
out.println("Character Encoding: " + request.getCharacterEncoding());
out.println("Content Length: " + request.getContentLength());
out.println("Content Type: "+ request.getContentType());
out.println("Auth Type: " + request.getAuthType());
out.println("HTTP Method: " + request.getMethod());
out.println("Path Info: " + request.getPathInfo());
out.println("Path Trans: " + request.getPathTranslated());
out.println("Query String: " + request.getQueryString());
out.println("Remote User: " + request.getRemoteUser());
out.println("Session Id: " + request.getRequestedSessionId());
out.println("Request URI: " + request.getRequestURI());
out.println("Servlet Path: " + request.getServletPath());
out.println("Accept: " + request.getHeader("Accept"));
out.println("Host: " + request.getHeader("Host"));
out.println("Referer : " + request.getHeader("Referer"));
out.println("Accept-Language : " + request.getHeader("Accept-Language"));
out.println("Accept-Encoding : " + request.getHeader("Accept-Encoding"));
out.println("User-Agent : " + request.getHeader("User-Agent"));
out.println("Connection : " + request.getHeader("Connection"));
out.println("Cookie : " + request.getHeader("Cookie"));
out.println("Created : " + session.getCreationTime());
out.println("LastAccessed : " + session.getLastAccessedTime());
2. 使用IE浏览器加载http://127.0.0.1:8080/LoginTest/index.jsp返回内容如下:
Protocol: HTTP/1.1 Scheme: http Server Name: 127.0.0.1 Server Port: 8080 Protocol: HTTP/1.1 Server Info: Apache Tomcat/6.0.18 Remote Addr: 127.0.0.1 Remote Host: 127.0.0.1 Character Encoding: null Content Length: -1 Content Type: null Auth Type: null HTTP Method: GET Path Info: null Path Trans: null Query String: null Remote User: null Session Id: E2C384C095E34AD355684EB554517FB1 Request URI: /LoginTest/index.jsp Servlet Path: /index.jsp Accept: */* Host: 127.0.0.1:8080 Referer : null Accept-Language : en-us Accept-Encoding : gzip, deflate User-Agent : Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; InfoPath.3; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET4.0C; .NET4.0E) Connection : Keep-Alive Cookie : JSESSIONID=E2C384C095E34AD355684EB554517FB1 Created : 1322294859981 LastAccessed : 1322294859981
3. 后面使用HttpClient不设置header信息加载http://127.0.0.1:8080/LoginTest/index.jsp信息如下:
Protocol: HTTP/1.1 Scheme: httpServer Name: 127.0.0.1 Server Port: 8080 Protocol: HTTP/1.1 Server Info: Apache Tomcat/6.0.18 Remote Addr: 127.0.0.1 Remote Host: 127.0.0.1 Character Encoding: null Content Length: -1 Content Type: null Auth Type: null HTTP Method: GET Path Info: null Path Trans: null Query String: null Remote User: null Session Id: null Request URI: /LoginTest/index.jspServlet Path: /index.jsp Accept: null Host: 127.0.0.1:8080 Referer : null Accept-Language : null Accept-Encoding : null User-Agent : Apache-HttpClient/4.1.1 (java 1.5) Connection : Keep-Alive Cookie : null Created : 1322293843369 LastAccessed : 1322293843369
分析: 由于这里纯粹加载页面,没有动用CookieStore自动管理Cookie,在上面没有能显示Cookie,SessionID的信息,区别于浏览器的的User-Agent,Cookie,SessionID,Accept,Accept-Language,Accept-Encoding等信息都没有进行设置.
对于爬取网站在HttpClient中设置Host,Referer,User-Agent,Connection,Cookie和爬取的频率和入口Url有讲究.
4. 考虑设置HttpClient的Header信息代码:
HashMap<String, String> headers = new HashMap<String, String>();
headers.put("Referer", p.url);
headers.put("User-Agent", "Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.2.6) Gecko/20100625
Firefox/3.6.6 Greatwqs");
headers.put("Accept","text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
headers.put("Accept-Language","zh-cn,zh;q=0.5");
headers.put("Host","www.yourdomain.com");
headers.put("Accept-Charset","ISO-8859-1,utf-8;q=0.7,*;q=0.7");
headers.put("Referer", "http://www.yourdomian.com/xxxAction.html");
HttpRequestBase httpget = ......
httpget.setHeaders(headers);
5. 由新的HttpClient执行http://127.0.0.1:8080/LoginTest/index.jsp得到的HTML信息如下:
Protocol: HTTP/1.1 Scheme: http Server Name: www.yourdomain.com Server Port: 80 Protocol: HTTP/1.1 Server Info: Apache Tomcat/6.0.18 Remote Addr: 127.0.0.1 Remote Host: 127.0.0.1 Character Encoding: null Content Length: -1 Content Type: null Auth Type: null HTTP Method: GET Path Info: null Path Trans: null Query String: null Remote User: null Session Id: null Request URI: /LoginTest/index.jsp Servlet Path: /index.jsp Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Host: www.yourdomain.com Referer : http://www.yourdomian.com/xxxAction.html Accept-Language : zh-cn,zh;q=0.5 Accept-Encoding : null User-Agent : Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9.2.6) Gecko/20100625 Firefox/3.6.6 Greatwqs Connection : Keep-Alive Cookie : null Created : 1322294148709 LastAccessed : 1322294148709