Java Web Crawling: Jsoup Parsing Tutorial

Teach you to use Jsoup to catch web pages without blocking the IP!

Recently, a number of friends do data collection with me to complain, said that the Java crawler is always blocked IP. this is something I have too much experience, last year to do e-commerce price monitoring, a day can be triggered more than a dozen times the CAPTCHA. Later found a trick - to Jsoup set on the proxy IP, just like wearing a bulletproof vest, today the practical experience of breaking open the crumpled to tell you.

Why do I have to use a proxy IP?

For example, if you live in a neighborhood that sends 100 people to the same supermarket every day to buy salt, the supermarket is sure to call the police the next day to say that someone is hoarding. It's the same thing with website protection systems.High-frequency access from a single IP must trigger risk controlThe first thing you need to do is to use ipipgo's Dynamic Proxy Pool. Using ipipgo's dynamic proxy pool is the equivalent of getting a new outfit every time you leave the house, and the website won't even recognize it as the same person.

Jsoup basic operation guide

First of all, the whole understand how to use Jsoup naked grab data (remember to add proxy at the end):

// The basic version of crawling
Document doc = Jsoup.connect("target url")
           .timeout(5000)
           .get();

This code grabs static pages, but it's like strolling down the street with no clothes on.Caught by site security in a minute.. Here's the kicker, how to put an agent vest on this code.

Proxy IP Access

Take ipipgo's proxy as an example of two common postures:

Focusing on the second way, theRemember to randomize the User-Agent.The ipipgo backend can directly generate matching request headers, just like role-playing, changing the persona for each visit.

Common Pitfalls Troubleshooting Manual

Q：Why is there a timeout report even though the agent is working?
A: 80% of the proxy server load is high, ipipgo's "Extreme Package" node response speed can be pressed to 200ms or less, just like the local direct connection.

Q: What should I do if all I get back is a CAPTCHA page?
A: three directions to troubleshoot: 1. request frequency don't be too wolf 2. cookies should be updated regularly 3. change ipipgo's residential agent, more realistic than the server room IP.

Package Selection Guide

Pick ipipgo's package according to your business needs:

• Long-lasting Package" for Public Opinion Monitoring - IP Survival for 24 Hours
• Use "Second Cut Package" for ticket and coupon grabbing - 5 seconds to change IP automatically
• Cross-country data collection picks 'global lines' - covering 195 countries

Recently they are having an event where they are giving away 1G traffic packages to new users. Fill in the registration [JSOUP2023] can also be more than 20% hours, pro-test effective. Encounter technical problems directly to the online customer service, response speed than peers at least three times faster.

lit. cold knowledge for avoiding pitfalls

Some sites will detect TLS fingerprints, which is when you have to use ipipgo'sAdvanced API Access ModeIf you want to use it, you can automatically adapt the encryption protocol of the target website. And then teach you a tawdry operation - the proxy IP list stored in Redis, when used randomly, so that the distributed collection of each node can rain evenly.

Finally, although the proxy IP can reduce the risk of banning, but do not swing a sledgehammer to other people's servers. Set a reasonable collection interval, with ipipgo's intelligent QPS control function, this is the long-term solution. The code is written again, but also have to pay attention to a sustainable development is not it?