Shulou(Shulou.com)06/03 Report--

This article will explain in detail how to crawl the data on the web page in the crawler. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

To build a web crawler, web page download is an essential step. This is not easy because there are many factors to consider, such as how to make better use of local bandwidth, how to optimize DNS queries, how to allocate network requests reasonably, and how to release server traffic.

1. Carry on the complex analysis to the HTML web page.

In fact, we can't access all HTML pages directly. When using AJAX's dynamic Web site, how to retrieve Javascript-generated content is also a problem. In addition, crawl traps that often occur in the network can cause numerous requests or cause crawlers to crash.

2. Although we should know a lot about building Web crawlers, in most cases, we just want to create crawlers for specific websites.

Not a general-purpose program like the Google crawler. Therefore, it is best to conduct in-depth research on the target website and choose valuable links to track to avoid additional costs caused by redundant or junk URLs. In addition, if the correct web crawling path can be found, the content of interest to the target site can be crawled in a predefined order.

The above mentioned is how to crawl data on a web page. Crawlers need to break the IP limit to crawl data, so you can consider using proxy ip.

This is the end of this article on "how to crawl data on a web page in a crawler". I hope the above content can be helpful to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.