htmlcleaner | 易学教程

python 反爬虫策略

阅读更多关于 python 反爬虫策略

1.限制IP地址单位时间的访问次数：分析：没有哪个常人一秒钟内能访问相同网站5次，除非是程序访问，而有这种喜好的，就剩下搜索引擎爬虫和讨厌的采集器了。弊端：一刀切，这同样会阻止搜索引擎对网站的收录适用网站：不太依靠搜索引擎的网站采集器会怎么做：减少单位时间的访问次数，减低采集效率 2.屏蔽ip 分析：通过后台计数器，记录来访者ip和访问频率，人为分析来访记录，屏蔽可疑Ip。弊端：似乎没什么弊端，就是站长忙了点适用网站：所有网站，且站长能够知道哪些是google或者百度的机器人采集器会怎么做：打游击战呗！利用ip代理采集一次换一次，不过会降低采集器的效率和网速(用代理嘛)。 3。利用js加密网页内容 Note:这个方法我没接触过，只是从别处看来分析：不用分析了，搜索引擎爬虫和采集器通杀适用网站：极度讨厌搜索引擎和采集器的网站采集器会这么做：你那么牛，都豁出去了，他就不来采你了 4.网页里隐藏网站版权或者一些随机垃圾文字，这些文字风格写在css文件中分析：虽然不能防止采集，但是会让采集后的内容充满了你网站的版权说明或者一些垃圾文字，因为一般采集器不会同时采集你的css文件，那些文字没了风格，就显示出来了。适用网站：所有网站采集器会怎么做：对于版权文字，好办，替换掉。对于随机的垃圾文字，没办法，勤快点了。 5.用户登录才能访问网站内容 * 分析

java爬虫简介（一）-＞实现数据抓取-＞httpClient请求接口数据

阅读更多关于 java爬虫简介（一）-＞实现数据抓取-＞httpClient请求接口数据

背景现如今，数据成为了越来越重要的网络资源，越来越有价值。无论是数据的分析还是前后端页面的数据交互，都离不开真实有效的数据。项目开发中数据甲方不可能实时提供，我们只能找到目标网站的数据进行抓取入库。数据作用决策支持提升效益数据的直接变现方式数据资源交易行业报告广告平台数据抓取的难点 1、目标网站有反爬取策略 2、目标网站模板会进行定时或实时变动 3、目标网站URL抓取失败 4、IP被封禁解决办法：购买代理IP库，随机获取IP进行数据抓取部署多个应用分别进行抓取，降低单位节点访问的频率设置每个页面抓取的时间间隔 5、用户登录限制数据抓取的原理实质上就是java程序模拟浏览器进行目标网站的访问，无论是请求目标服务器的接口还是请求目标网页内容，都是要在java程序中对数据进行解析。最简单的抓取方式有httpclient请求目标服务器接口，jsoup请求目标页面内容，把请求的数据进行解析然后入库。另外要做好爬取的实时监控，如果URL请求失败3次，就放弃该URL的抓取。总体架构的设计 1、数据流向 1、确定数据爬取目标 2、数据采集 1、下载数据 2、解析数据 3、存取接入库（database，HDFS） 3、分析查询服务 2、模块划分 1、数据采集模块 2、数据分析模块 3、报表管理模块 4、系统管理与监控模块 3、模块解读技术选型数据采集层 JSoup

Generate PDF file in an appropriate format

阅读更多关于 Generate PDF file in an appropriate format

问题 For my use, I created a PDF file using flying-saucer library. It was a legacy HTML so I cleaned out the XHTML using HTMLCleaner library. After this I serialize the XML as string then pass it to the iText module of flying-saucer to render it and subsequently create the PDF. This PDF I place it in the OutputStream . After the response is committed I get a dialog asking to save or open it. However it does not get saved as PDF file. I have to right-click and open it in Adobe or any PDF reader.

Get the specific word in text in HTML page

阅读更多关于 Get the specific word in text in HTML page

问题 If I have the following HTML page <div> <p> Hello world! </p> <p> <a href="example.com"> Hello and Hello again this is an example</a></p> </div> I want to get the specific word for example 'hello' and change it to 'welcome' wherever they are in the document Do you have any suggestion? I will be happy to get your answers whatever the type of parser you use? 回答1: This is easy to do with XSLT. XSLT 1.0 solution : <xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"

Get the specific word in text in HTML page

阅读更多关于 Get the specific word in text in HTML page

Find Xpath of an element in a html page content using java

阅读更多关于 Find Xpath of an element in a html page content using java

问题 I'm begginer to xpath expression , I have below url : http://www.newark.com/white-rodgers/586-902/contactor-spst-no-12vdc-200a-bracket/dp/35M1913?MER=PPSO_N_P_EverywhereElse_None which holds html pagecontent,using following xpaths it results same ul element in javascript: //*[@id="moreStock_5257711"] //*[@id="priceWrap"]/div[1]/div/a/following-sibling::ul //html/body/div/div/div/div/div/div/div/div/div/div/a/following-sibling::ul using this xpaths how sholud i get same ul element in java I

Is there a way in Ant (using Groovy?) to post info to an http URL and then parse the response?

阅读更多关于 Is there a way in Ant (using Groovy?) to post info to an http URL and then parse the response?

问题 I've found a way to read an HTML page in Ant with Groovy + HTMLCleaner (see: Parse HTML using with an Ant Script ) but I am unable to find a way to first POST some data to a URL and then get a response and be able to parse that with HTMLCleaner (or something similar). Is this posible? 回答1: You can use the groovy REST client, which is part of the HTTPBuilder project. <target name="invoke-webservice"> <taskdef name="groovy" classname="org.codehaus.groovy.ant.Groovy" classpathref="build.path"/>

xPath expression: Getting elements even if they don't exist

阅读更多关于 xPath expression: Getting elements even if they don't exist

问题 I have this xPath expression that I'm putting into htmlCleaner: //table[@class='StandardTable']/tbody/tr[position()>1]/td[2]/a/img Now, my issue is that it changes, and some times the /a/img element is not present. So I would like an expression that gets all elements //table[@class='StandardTable']/tbody/tr[position()>1]/td[2]/a/img when /a/img is present, and //table[@class='StandardTable']/tbody/tr[position()>1]/td[2] when /a/img is not present. Does anyone hav any idea how to do this? I

Using jsoup to escape disallowed tags

阅读更多关于 Using jsoup to escape disallowed tags

问题 I am evaluating jsoup for the functionality which would sanitize (but not remove!) the non-whitelisted tags. Let's say only <b> tag is allowed, so the following input foo <b>bar</b> <script onLoad='stealYourCookies();'>baz</script> has to yield the following: foo <b>bar</b> <script onLoad='stealYourCookies();'>baz</script> I see the following problems/questions with jsoup: document.getAllElements() always assumes <html> , <head> and <body> . Yes, I can call document.body().getAllElements()

Remove MS Word “HTML” using PHP [duplicate]

阅读更多关于 Remove MS Word “HTML” using PHP [duplicate]

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: What is the best free way to clean up Word HTML? PHP to clean-up pasted Microsoft input I allow clients to enter notes in a rich text editor, and have only recently upgraded to ckEditor 3x, which strips MS word classes, styles, and comments by default (when users paste into the editor object). So moving forward I'm all set. I've recently had a need to clean up 5 years worth of notes some of which have MS word

订阅 htmlcleaner